Introduction
============

Blood is a major vital component of the human body. Since it cannot be manufactured artificially, and can only be obtained from human resources,[@b1-ijgm-7-401] blood donation has become an important and essential process that every health care facility should take into consideration.[@b2-ijgm-7-401] Recently, both developing and developed countries are finding it hard to recruit regular donors to donate six times per year.[@b3-ijgm-7-401],[@b4-ijgm-7-401] Blood donors are differentiated into: voluntary, family replacement, and remunerated or paid donors.[@b5-ijgm-7-401] Due to the increased number of blood borne infections caught from paid donors,[@b6-ijgm-7-401],[@b7-ijgm-7-401] developing and developed countries are trying to obtain blood from voluntary donors only. Confining the blood donor population to voluntary donors only, which is the World Health Organization's instructions on blood donation,[@b8-ijgm-7-401] is not an easy task, as identified in previous studies.[@b2-ijgm-7-401],[@b4-ijgm-7-401],[@b9-ijgm-7-401] Mascaretti et al reported that only five out of 17 European countries accept blood from voluntary donors.[@b10-ijgm-7-401]

Blood donation criteria was recently tightened for the sake of blood quality and safety, which resulted in a severe shortage of blood storage in the blood banks.[@b11-ijgm-7-401],[@b12-ijgm-7-401] What makes it more challenging is the increased demand for blood due to more advanced surgical techniques, a dramatic increase in the number of trauma patients, and new modalities in cancer treatment.[@b13-ijgm-7-401],[@b14-ijgm-7-401] A recent survey conducted in the US showed a spectacular increase in the demand for blood transfusions in 10 years: 1.1 million transfusions in 1997 against 2.7 million in 2007.[@b15-ijgm-7-401]

Several factors play a role in the recruitment and willingness of people to donate blood voluntarily. Various studies have revealed a significant association between the donor population and their demographic data[@b13-ijgm-7-401],[@b14-ijgm-7-401],[@b16-ijgm-7-401] in terms of sex, age, and level of education. With regards to knowledge of blood donation, studies have shown that the more knowledgeable a subject is about blood and the need for it, the more likely they are to be a previous donor.[@b17-ijgm-7-401],[@b18-ijgm-7-401] Investigators in different study settings had similar responses from subjects, who identified the number one reason behind their willingness to donate was being aware of blood needs among patients.[@b2-ijgm-7-401],[@b16-ijgm-7-401],[@b19-ijgm-7-401],[@b20-ijgm-7-401]

The attitudes towards blood donation differ between donors and non-donors. Altruism is the major and most commonly reported reason motivating a subject to donate.[@b14-ijgm-7-401] Religious act, national duty, quality of service at the blood bank, and family needs or encouragement were all positive attitudes associated with one's decision to donate.[@b14-ijgm-7-401],[@b21-ijgm-7-401] On the other hand, there were negative attitudes that were reported from non-donors, fear being the most commonly reported.[@b2-ijgm-7-401],[@b13-ijgm-7-401],[@b14-ijgm-7-401],[@b18-ijgm-7-401],[@b21-ijgm-7-401] Nevertheless, those negative attitudes are not all true, as the population suffers from rooted misconceptions that need to be corrected. Physical weakness, age limitations, high risk of infections, and blood being sold to patients, are incorrect beliefs existing among the public.[@b3-ijgm-7-401],[@b22-ijgm-7-401],[@b23-ijgm-7-401] Correction of these misconceptions is essential; the media, especially television, should be utilized in this situation since it is the number one source of information in some communities.[@b14-ijgm-7-401]

In Saudi Arabia, non-remunerated, voluntary blood donors are the only source of blood donation. A previous local study conducted by Abdel Gader et al showed a strong positive attitude towards blood donation.[@b21-ijgm-7-401] However, after a recent incident of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome transmission to a young Saudi girl following blood transfusion,[@b24-ijgm-7-401] the perception of the Saudi public towards blood donation has possibly changed. The aims of the current study were to 1) assess the level of Saudi public knowledge and attitude towards blood donation and 2) describe previous experiences and barriers to blood donation. Elaboration of the strategies that motivate people to donate blood could lead to the maintenance of a sufficient blood source.

Methods
=======

Study subjects
--------------

Adults over the age of 18 years (both male and female) in shopping malls in the city of Riyadh (the capital city of Saudi Arabia), who provided verbal consent, were eligible to participate in the survey. Non-Saudi subjects and those not willing to participate were excluded.

Study design
------------

A cross-sectional study design was used.

Study population and sampling technique
---------------------------------------

Based on a previous study that showed 26% of the subjects exhibited a positive attitude towards blood donation,[@b14-ijgm-7-401] with a margin of error of 4%, and a 95% confidence interval, the estimated required sample size was 464. A number of large malls that serve different geographical areas of Riyadh were identified. Proportional quota sampling was used to ensure that respondents were demographically representative of the general population with quotas based on age, sex, work status, region, and social class. Adults shopping in these malls within the 2 weeks between 8--22 July, 2013, who were willing to participate in the study were interviewed. Each data collector spent an average of 3 hours in each mall, at randomly chosen times of the day to recruit participants. A total of 469 subjects (including both sexes) were successfully interviewed.

Data collection methods
-----------------------

The study was based on an interview questionnaire. The questionnaire was initially designed by the research team according to a previously validated questionnaire.[@b14-ijgm-7-401] The interview questionnaire was translated into Arabic. The test--retest reliability was measured in a pilot study of ten participants. Discussions with various relevant experts at King Abdullah International Medical Research Center (Riyadh, Saudi Arabia) confirmed the content validity and feasibility of the questionnaire to ensure the relevance and clarity of the questions. Several additions and amendments were made to ensure that the questions were valid in a Saudi context. The questionnaire sheet consisted of 38 questions, divided into four parts:

-   The first part collected sociodemographic data of the participant, such as age, sex, marital status, and educational level. It also assessed participant's background and their sources of information regarding blood donation.

-   The second part assessed the participant's level of knowledge regarding blood donation. This part consisted of a total of eleven statements. These statements included if there is an age limitation on blood donation, if people of any blood group can donate, and if women can donate when menstruating. Other statements asked about the possibility of certain consequences (eg, anemia and transmission of infection to donor or receiver) following blood donation. In addition, the participants, awareness of preventive conditions for blood donation were examined. These conditions were listed as a history of drug abuse or an unsafe sexual relationship, a diagnosis of anemia, diabetes, hypertension, or pregnancy. Furthermore, it asked if laboratories tested donated blood for HIV, hepatitis, and syphilis, and if there is a sex preference for blood donation. Each question was rated zero for a wrong answer and one for the right answer. An overall knowledge score was then calculated by adding the scores for the statements. Thus, the highest possible score was eleven points. Percentage mean scores (PMS) were calculated and the level of knowledge was classified as "good" (\>80%), "average" (60%--80%) and "poor" (\<60%).

-   The third part assessed attitudes toward blood donation. This part included ten attitude statements to be answered using a five-point Likert scale. The statements were regarding the participants' beliefs and perceptions about blood donation. Participants gave "strongly agree", "agree", "not sure", "disagree", or "strongly disagree" responses to all of the questions.

    Negative attitude statements were scored from five (for participants who strongly agreed) to one (for participants who strongly disagreed). The opposite of this scoring system was used for the positive attitude statements. Accordingly, the total attitude score ranged between eleven and 55 points. PMS were calculated. Levels of attitude were classified as: "positive" (\>80%), "neutral" (60%--80%), and "negative" (\<60%).

-   The fourth part asked whether the participant had ever donated blood or not, the frequency of donation, and reasons for not donating blood.

Ethical considerations
----------------------

Participation in the study was voluntary, and each participant was able to withdraw from the study at any time. The investigators explained the aim of the study to the participants. The study protocol received ethical approval from the Saudi National Guard Health Affairs (Riyadh, Saudi Arabia) (application number RR 013/44).

Data analysis
-------------

Data entry and statistical analysis were performed using SPSS^®^ version 20.0 (IBM Corporation, Armonk, NY, USA). Descriptive statistics, such as percentages, frequencies, means, and standard deviations, were used to measure the demographic variables and the responses to knowledge and attitude statements. Analytical statistics were applied to investigate the association of knowledge and attitude with demographic variables. Multiple linear regression analyses were performed to identify the significant predictors for frequency of blood donation. Statistical significance was set at *P*\<0.05 for all analyses.

Results
=======

The study sample comprised 75.9% men and 24.1% women. A total of 48.8% were under 30 years old, 54.6% of participants' level of education was below university level, and 58.8% were currently married. More than half of all participants (53.3%) reported a previous history of blood donation, 66% of whom were males and only 13.3% females (*χ*^2^=95.84, *P*\<0.001). Frequency of donation ranged between 1--38 times, with an average frequency of 2.61±4.72 times. This average was significantly higher in males (3.37±5.18) than in females (0.20±0.64; *t*=11.26; *P*\<0.001). Repeat donors constituted 39.3% of all participants (50.3% males; 4.4% females). Previous blood transfusion to one of the family members and/or a relative was reported by 35.2% of all participants (30.6% males; 49.6% females; *χ*^2^=13.49; *P*\<0.001) ([Table 1](#t1-ijgm-7-401){ref-type="table"}).

[Figure 1](#f1-ijgm-7-401){ref-type="fig"} shows the reasons provided for not donating blood, divided by sex. Lack of time ranked first as the reason for not donating (52.5%), followed by inability to access the blood bank for donation (33.8%), family discouragement (28.8%), fear of anemia (21.9%) fear of infection (14.6%), fear of the needle (11.9%), and lastly, fear of the sight of blood (8.2%). A lack of time was reported at a significantly higher frequency by males (*χ*^2^=5.30; *P*=0.021), whereas a significantly higher number of females reported an inability to reach the blood bank (*χ*^2^=11.66; *P*=0.001), and fear of anemia (*χ*^2^=19.73; *P*\<0.001).

[Table 2](#t2-ijgm-7-401){ref-type="table"} shows the levels of knowledge and attitude of the Saudi public toward blood donation by sex. It shows that about half (48.0%) of the study sample had a poor level of knowledge, with only 11.9% having a good level knowledge on blood donation, with no significant sex difference (*χ*^2^=3.48; *P*=0.175). The level of attitude towards blood donation was neutral for the majority of subjects (61.6%), with 31.6% reporting a positive attitude and only 6.8% reporting a negative attitude. Participants with a positive attitude constituted 36.2% of all males compared to only 16.8% of all females (*χ*^2^=15.34; *P*\<0.001).

[Table 3](#t3-ijgm-7-401){ref-type="table"} shows the responses to the knowledge statements on blood donation. The majority of participants correctly identified that those with history of drug abuse (67%), illegal sexual relations (72.5%), or those with diabetes, hypertension, and/or anemia (75.7%) are not allowed to donate blood. The majority correctly reported that blood donation could cause transmission of infection to the receiver (73.8%), but only 22.8% correctly reported the possibility of transmission to the donor. About half (68%) correctly reported that people with any blood group can donate blood, yet only one-third correctly reported that age (39.2%) and menstruation (33.7%) are not considered as limitations for donation.

[Table 4](#t4-ijgm-7-401){ref-type="table"} shows the responses to attitude statements towards blood donation. Almost all participants (96%) agreed that donation is altruistic, and the majority disagreed with donation if the person donating is receiving leave from work (75.1%) or incentives (92.7%). The majority agreed that donation is a national duty (82.6%) and that when they donate blood they feel they are donating to a family member or a friend (91.9%), and 70% agreed that their families consider donation a valuable act and encourage them to donate. However, 34.1% agreed that they would only donate blood if they were sure that the donation will be given to them or their family members in the future. Those who considered donation a religious duty constituted 58.7% of all participants.

[Table 5](#t5-ijgm-7-401){ref-type="table"} shows the association between knowledge and attitude PMS for blood donation with some sociodemographic and blood donation characteristics. PMS of knowledge was significantly higher in male participants (*t*=2.68; *P*=0.008) of a higher education (*t*=3.32; *P*=0.001), who were married (*t*=2.11; *P*=0.036), and who had reported previous experience with blood transfusion (*t*=2.86; *P*=0.004). After adjustment for potential confounders, this association was significant only for education level (*P*=0.001) and previous experience with blood transfusion (*P*=0.021). Further, PMS for attitude was significantly higher for males (76.45±12.12) than for females (72.32±9.69; *t*=3.70; *P*\<0.001). This sex difference in attitude PMS remained significant (*P*=0.001) after adjusting for all other confounding variables. A positive and direct relationship between attitude and awareness PMS was shown in this study (*r*=0.301; *P*\<0.001).

[Figure 2](#f2-ijgm-7-401){ref-type="fig"} shows that participants with a previous history of blood donation had significantly higher PMS for knowledge (59.56% versus 56.37%; *t*=2.03; *P*=0.043) and higher PMS for attitude (78.24% versus 72.27%; *t*=5.75; *P*\<0.001) than did those with no such history.

[Table 6](#t6-ijgm-7-401){ref-type="table"} shows the significant predictors of frequency for blood donation practice among the Saudi public. It shows that higher knowledge score (*t*=2.59; *P*=0.01), higher attitude score (*t*=3.26; *P*=0.001), and male sex were all significant predictors of higher frequency of blood donation.

Discussion
==========

The shortage of blood in most of the blood banks in different countries is due to the increase in demand with few people coming to donate voluntarily.[@b2-ijgm-7-401] As non-remunerated donated blood is the only blood source in Saudi Arabia, people's motivation should be improved to keep the blood supply levels sufficient. Hence, more attempts should be made to attract society members for blood donation.[@b25-ijgm-7-401] In the present study, around half of the study sample reported a history of previous donation. Among the male subjects, 66% were previous blood donors, whereas among the females, only 13.3% were previous donors. This finding was similar to the finding of a study conducted in Iran,[@b14-ijgm-7-401] where 59.8% of males and 15.9% of females were previous donors. Of the 250 (35.3%) donors, 235 (94%) were males and only 15 (6%) were females. This result is similar to what was observed in India, where 93% of donors were males and 7% were females.[@b26-ijgm-7-401]

It has been reported that lack of time, and fear of complications are barriers to blood donation in both sexes.[@b13-ijgm-7-401] Time constraints may reflect the changing structure of society. In the current study, having no time was reported by more than half of male participants. This might be attributable to the Saudi culture, which obligates males to fully satisfy their families' needs and may lead to an inability to find free time to visit the donation centers. It has been noted that donors in the UK suffer significant out-of pocket costs, as well as lose of leisure time, and, in the economy more broadly, lost productivity.[@b27-ijgm-7-401]

Practical problems and discomfort during donation were important reasons why women reported having stopped donation.[@b9-ijgm-7-401] Reducing women's discomfort during donation may therefore increase return rates.[@b28-ijgm-7-401],[@b29-ijgm-7-401] In the current study, two main reasons were reported by females. First was the inability to reach the donation centers, as reported by nearly half of female participants, which might be explained by the prohibition of females to drive in Saudi Arabia or the long distance to the donation centers. Second was the fear of becoming anemic, which was reported by more than one-third of females, although only 8% of them reported that donation may cause anemia. A study carried out among Dhaka University students in Bangladesh showed that only 16% of the donors ever donated voluntarily as physical harm and fear were found to be the common reasons for not donating.[@b30-ijgm-7-401] In Granada, fears deterred 32.3% from donating.[@b31-ijgm-7-401] The fear of becoming infected with HIV by donating blood was also a prevalent deterrent amongst the Scottish population, and this adversely affected their blood donation habit.[@b32-ijgm-7-401] In the current study, only 16% and 13% of female and male participants respectively reported fear of infection as a reason for not donating. Although the majority of participants reported that donation can cause transmission of infection to receivers, only 22% reported possible transmission to donor. This may explain why transmission of infection was not stated as a reason for not donating in the current study. Fear has been considered as the most commonly reported negative attitude on blood donation.[@b2-ijgm-7-401],[@b13-ijgm-7-401],[@b14-ijgm-7-401],[@b18-ijgm-7-401],[@b21-ijgm-7-401] In the current study, fear of the sight of blood was the reason for not donating in 6% and 11% of males and females, respectively.

Blood donor recruitment programs are required for the recruitment and retention of "safe" donors, and the proportion of repeat donors is an indicator of their success. This proportion is between 1%--70% (median 20%) in the least developed countries and up to 85% (median 47%) in developing countries, compared with values between 30%--90% (median 88%) for developed countries.[@b6-ijgm-7-401] In the current study, 39.2% of those with history of previous donation were repeat donors of more than once, constituting half of male participants, a finding that is encouraging. Because the prevalence of markers for transmissible diseases is usually lower among repeat donors than among first time donors,[@b33-ijgm-7-401] an increased proportion of repeat donors is, in general, associated with decreased costs due to lower discard rates, as well as with improved blood safety.[@b6-ijgm-7-401]

What makes an individual give blood? The factors influencing the individuals' decision to give blood are a collection of individual specific observable characteristics, such as sociodemographic factors, and unobservable characteristics, such as the degree of altruism.[@b4-ijgm-7-401] Studies have been carried out to examine how blood donors differ from non-donors with respect to their socioeconomic and demographic characteristics, such as sex, age, marital status, ethnicity, levels of education and income.[@b4-ijgm-7-401],[@b25-ijgm-7-401],[@b34-ijgm-7-401],[@b35-ijgm-7-401] In the current study, male sex and levels of knowledge and attitude on blood donation were the significant predictors of the frequency of donation.

There is some evidence that suggests the more knowledge one has of the blood donation process and the need for blood increases, the more likely one is to donate blood.[@b17-ijgm-7-401],[@b18-ijgm-7-401] When knowledge PMS were compared between donors and non-donors, it was shown that donors had a significantly higher PMS of knowledge than non-donors. This is in agreement with a study by Dubey et al, where donors -- specifically voluntary donors -- had better knowledge than others.[@b36-ijgm-7-401] This finding was evident after adjustment. However, his finding was not in agreement with another investigation administered to the students of Thai university that indicated that greater knowledge about blood donation does not necessarily lead to donation.[@b37-ijgm-7-401]

It is clear that a lack of knowledge about blood donation or having false ideas will lead to a decrease in willingness to participate in blood donation.[@b1-ijgm-7-401] The present study showed in general, a poor level of knowledge about blood donation. The most commonly reported misconception in the current study was denying that blood donation can transmit an infection to the donor. A different result was observed in a study conducted in Nigeria, where 52.4% of donors believed that they could contact HIV and/or hepatitis infection from blood donation.[@b3-ijgm-7-401] Meanwhile, in a recent study, the risk of transmission of infectious and blood borne diseases was the reason that 40.4% of women were unwilling to donate blood.[@b38-ijgm-7-401] Another misconception was that women could not donate blood because of menstruation. Other studies reported loss of fertility and physical weakness as false beliefs about blood donation.[@b36-ijgm-7-401] Participants also had poor knowledge about the age limitation on blood donation and women's ability to donate with regard to menstruation. However, a study conducted in India showed that the majority of subjects knew about the minimum age to donate blood.[@b26-ijgm-7-401] In a study conducted in Saudi Arabia on 500 adult males, only 6% of men were aware of the suitable age for blood donation while 28% knew about the minimum necessary weight.[@b16-ijgm-7-401]

The decision to donate blood is influenced by some covariates such as altruism, social behavior, social pressure, and replacement.[@b34-ijgm-7-401],[@b39-ijgm-7-401] The highest motivational factor reported by the subjects in the current study was that donation gives a sensation of altruism, where almost all participants (96%) agreed that donation is altruistic, agreeing with the Iranian population.[@b13-ijgm-7-401] Other studies reported personal or family benefits, financial rewards, and creating opportunities for donation as motivating factors to their donor populations.[@b3-ijgm-7-401],[@b26-ijgm-7-401] The majority of participants in the current study think that their donation would encourage others to donate. Although some findings indicate that using non-monetary incentives may help increase the number of lapsed blood donors, shifting to permanent incentives may make donors consider blood banks as a non-altruistic service.[@b11-ijgm-7-401] In the current study, the majority disagreed with donation if the donor is receiving leave from work or incentives. The majority agreed that donation is a national duty, and that when they donate blood they feel they are donating to a family member or a friend. Family discouragement was a reason for not donating for a few participants, yet the majority agreed that their families consider donation a valuable act and encourage them to donate. However, 34.1% agreed that they would donate blood only if they were sure that the donation will be given to them or their family members in the future. More than half of participants considered donation a religious duty.

The level of knowledge was significantly predicted by university education and previous experience with blood transfusion in a family member. The more educated a person is, the more he knows about blood donation -- this was observed in the current study as well as in the study in Iran.[@b13-ijgm-7-401] Education remained a significant predictor of knowledge level after adjusting for all possible confounders. The overall attitude of the studied subjects was neutral, with only 31.6% reporting a positive attitude to donation, a figure that reflects generally, an unfavorable attitude to donation, compared to 99% in a previous study by Abdel Gader et al.[@b21-ijgm-7-401] This unfavorable attitude to donation in the present study may reflect the possible negative impact of an incident of HIV transmission to a young Saudi girl following blood transfusion[@b24-ijgm-7-401] on public perception to donation. Males had a better attitude than females, which is the opposite of what had been found in a similar study.[@b13-ijgm-7-401] Male sex was also a significant predictor of frequent blood donation in the present study, together with the higher attitude score to donation. Experience of prior blood donation, number of previous donations, and duration from last donation are correlated with future behavior.[@b40-ijgm-7-401]--[@b42-ijgm-7-401] Individual attachment with someone who donates blood, or knowing people who have received donated blood all could influence willingness to donate blood.[@b30-ijgm-7-401],[@b43-ijgm-7-401],[@b44-ijgm-7-401] In the current study, one-third of the study sample reported having someone in the family to whom blood was donated. This previous experience with blood transfusion was significantly associated with the level of knowledge of participants. The positive and direct relationship between attitude and awareness in this current study were similar to what has been reported by two studies conducted in Yazd, Iran.[@b13-ijgm-7-401],[@b45-ijgm-7-401]

This study has some limitations. First, because the study was cross-sectional, a temporal relationship between exposure and outcome cannot be established. It is clear that the true causal relationships among all of the identified variables are complex and often reciprocal. For example, knowledge and attitude of the public on blood donation may be affected by previous donations. Second, the small number of females who participated in the study may not be representative of the whole female population in Saudi Arabia, and this would affect the generalizability of the results.

Conclusion
==========

-   Prevalence of blood donation was less than satisfactory among the Saudi public, probably due to misconceptions, poor knowledge and unfavorable attitudes to donation. An intensive campaign should be implemented to educate and encourage the public about blood donation to alleviate their fears and change their perceptions. The level of education of the donors, coupled with a positive attitude shown in the study, could be the driving factor in recruiting voluntary blood donors.

-   Barriers to blood donations have to be thoroughly investigated. Qualitative surveys of blood donation may also provide a rich source of information on individuals' decisions to give blood. Adequate incentives in the form of honors, awards, or any other incentives that suit the community could be developed for these donors. It may also be useful to target men and women, perhaps by making donations easier for them by providing mobile blood collection nearer to individual's places of work and so reduce their time costs for donating.

This study was initiated and funded by the King Abdullah International Medical Research Center. This work was presented at the fifth Research Summer School program of the King Abdullah International Medical Research Center in July 2013.

**Disclosure**

The authors report no conflicts of interest in this work.

![Reasons for not donating among the Saudi public by sex.](ijgm-7-401Fig1){#f1-ijgm-7-401}

![Percentage mean scores for knowledge and attitude towards blood donation by previous donation among the Saudi public.\
**Notes:** "Yes" denotes previous blood donation and "No" denotes no previous donation.](ijgm-7-401Fig2){#f2-ijgm-7-401}

###### 

Personal characteristics and donation-related characteristics

  -----------------------------------------------------------------------------------------------------------------------------------------------------------------------
                               Male (N=356)                                                            Female (N=113)   Total (N=469)                              
  ---------------------------- ----------------------------------------------------------------------- ---------------- --------------- ------ ------------------- ------
  Age group                                                                                                                                                        

   \<30 years                  172                                                                     48.3             57              50.2   229                 48.8

   ≥30 years                   184\                                                                    51.7             56              49.6   240                 51.2
                               *χ*^2^=0.155; *P*=0.69                                                                                                              

  Education level                                                                                                                                                  

   ≤ High school               209                                                                     58.7             47              41.6   256                 54.6

   University                  147\                                                                    41.3             66              85.4   213                 45.4
                               *χ*^2^=10.135; *P*=0.001[\*](#tfn1-ijgm-7-401){ref-type="table-fn"}                                                                 

  Marital status                                                                                                                                                   

   Married                     202                                                                     56.7             74              65.5   276                 58.8

   Unmarried                   154\                                                                    43.3             36              34.5   193                 41.2
                               *χ*^2^=2.709; *P*=0.10                                                                                                              

  Previous donation                                                                                                                                                

   None                        121                                                                     34.0             98              86.7   219                 46.7

   Once                        56                                                                      15.7             10              8.8    66                  14.1

   2--4 times                  89                                                                      25.0             4               3.5    93                  19.8

   ≥5 times                    90\                                                                     25.3             1               0.9    91                  19.4
                               *χ*^2^=100.204; *P*\<0.001[\*](#tfn1-ijgm-7-401){ref-type="table-fn"}                                                               

  Previous blood transfusion                                                                                                                                       

   Yes                         109                                                                     30.6             56              49.6   165                 35.2

   No                          247\                                                                    69.4             57              50.4   304                 64.8
                               *χ*^2^=13.49; *P*\<0.001[\*](#tfn1-ijgm-7-401){ref-type="table-fn"}                                                                 

  Mean ± SD                    32.24±11.57                                                                              31.11±8.82             31.97±10.98\        
                                                                                                                                               *t*=1.10, *P*=0.2   
  -----------------------------------------------------------------------------------------------------------------------------------------------------------------------

**Notes:**

Statistically significant. N denotes the total number of males, females and both; n denotes the number of each category in different variables.

**Abbreviation:** SD, standard deviation.

###### 

Levels of knowledge and attitude of the Saudi public in regards to blood donation by sex

  ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Sex      Knowledge level          Attitude level                                                                                                                            
  -------- ------------------------ ---------------- ----- ------ ----- ------ --------------------------------------------------------------------- ------ ----- ------ ---- -----
  Male     39                       11.0             138   38.7   179   50.3   129                                                                   36.2   203   57.0   24   6.8

  Female   17                       15.0             50    44.2   46    40.8   19                                                                    16.8   86    76.1   8    7.1

  Total    56\                      11.9             188   40.1   225   48.0   148\                                                                  31.6   289   61.6   32   6.8
           *χ*^2^=3.48; *P*=0.175                                              *χ*^2^=15.34; *P*\<0.001[\*](#tfn3-ijgm-7-401){ref-type="table-fn"}                            
  ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

**Note:**

Statistically significant *P*-value.

###### 

Response to knowledge statements about blood donation

  Knowledge                                                                                  Yes   No                                                Do not know   Sex difference                                                 
  ------------------------------------------------------------------------------------------ ----- ------------------------------------------------- ------------- ------------------------------------------------- ----- ------ ---------------------------------------------------------------
  Is there any age limitation on blood donation?                                             184   39.2[\#](#tfn4-ijgm-7-401){ref-type="table-fn"}   151           32.2                                              134   28.6   7.84 (*P*=0.02)[\*](#tfn5-ijgm-7-401){ref-type="table-fn"}
  Can women donate blood while menstruating?                                                 158   33.7[\#](#tfn4-ijgm-7-401){ref-type="table-fn"}   143           30.5                                              168   35.8   100.76 (*P*\<0.01)[\*](#tfn5-ijgm-7-401){ref-type="table-fn"}
  Can people with any blood group donate blood?                                              319   68.0[\#](#tfn4-ijgm-7-401){ref-type="table-fn"}   73            15.6                                              77    16.4   3.007 (*P*=0.22)
  Does blood donation cause anemia?                                                          39    8.3                                               339           72.3[\#](#tfn4-ijgm-7-401){ref-type="table-fn"}   91    19.4   2.37 (*P*=0.31)
  Could blood donation cause transmission of infection to the donor?                         107   22.8[\#](#tfn4-ijgm-7-401){ref-type="table-fn"}   307           65.5                                              55    11.7   0.2 (*P*=0.91)
  Could blood donation cause transmission of infection to the receiver?                      346   73.8[\#](#tfn4-ijgm-7-401){ref-type="table-fn"}   77            16.4                                              46    9.8    7.49 (*P*=0.02)[\*](#tfn5-ijgm-7-401){ref-type="table-fn"}
  Is someone with a history of drug abuse allowed to donate blood?                           33    7.0                                               314           67.0[\#](#tfn4-ijgm-7-401){ref-type="table-fn"}   122   26.0   2.727 (*P*=0.26)
  Is someone with a history of an unsafe sexual relationship allowed to donate blood?        49    10.4                                              340           72.5[\#](#tfn4-ijgm-7-401){ref-type="table-fn"}   80    17.1   4.217 (*P*=0.12)
  Are anemic, diabetic, or hypertensive people or pregnant ladies allowed to donate blood?   31    6.6                                               355           75.7[\#](#tfn4-ijgm-7-401){ref-type="table-fn"}   83    17.7   0.578 (*P*=0.75)
  Does the laboratory test donated blood for HIV, hepatitis, and syphilis?                   369   78.7[\#](#tfn4-ijgm-7-401){ref-type="table-fn"}   32            6.8                                               68    14.5   20.13 (*P*\<0.01)[\*](#tfn5-ijgm-7-401){ref-type="table-fn"}

**Notes:**

The correct answer

statistically significant. Sex differences were measured by the χ^2^ test.

**Abbreviation:** HIV, human immunodeficiency virus.

###### 

Response to attitude statements about blood donation

  Attitude                                                                                                                Strongly agree   Agree                                             Neutral   Disagree                                          Strongly disagree   Sex difference                                                                                                                   
  ----------------------------------------------------------------------------------------------------------------------- ---------------- ------------------------------------------------- --------- ------------------------------------------------- ------------------- ---------------- ----- ------------------------------------------------- ----- ------------------------------------------------- ---------------------------------------------------------------
  I think that blood donation is altruistic                                                                               338              72.1[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   112       23.9[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   9                   1.9              9     1.9                                               1     0.2                                               4.01 (*P*=0.4)
  I do not think that my donation will encourage others to donate                                                         21               4.5                                               70        14.9                                              76                  16.2             162   34.5[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   140   29.9[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   27.4 (*P*\<0.001)[\*](#tfn8-ijgm-7-401){ref-type="table-fn"}
  I would donate blood if I was assured that the donated blood will be given to me or to one of my family in the future   83               17.7                                              77        16.4                                              34                  7.2              187   39.9[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   88    18.8[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   7.78 (*P*=0.1)
  My family and friends consider blood donation as an important valuable act and encourage me to donate                   133              28.4[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   197       42.0[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   56                  11.9             69    14.7                                              14    3.0                                               9.9 (*P*=0.04)[\*](#tfn8-ijgm-7-401){ref-type="table-fn"}
  I do not think that blood donation is a religious duty                                                                  18               3.8                                               51        10.9                                              82                  17.5             159   33.9[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   159   33.9[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   57.48 (*P*\<0.001)[\*](#tfn8-ijgm-7-401){ref-type="table-fn"}
  I think that blood donation is a national duty                                                                          209              44.6[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   178       38.0[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   38                  82.0             27    5.8                                               17    3.6                                               28.6 (*P*\<0.001)[\*](#tfn8-ijgm-7-401){ref-type="table-fn"}
  I would donate blood if there were incentives or rewards                                                                12               2.6                                               14        3.0                                               8                   1.7              155   33.0[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   280   59.7[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   5.45 (*P*=0.244)
  Donating blood makes me feel like I have helped one of my family members or friends                                     228              48.6[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   203       43.3[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   19                  4.1              11    2.3                                               8     1.7                                               11.18 (*P*=0.025)[\*](#tfn8-ijgm-7-401){ref-type="table-fn"}
  I would donate blood if given leave from work                                                                           46               9.8                                               46        9.8                                               25                  5.3              149   31.8[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   203   43.3[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   22.0 (*P*\<0.001)[\*](#tfn8-ijgm-7-401){ref-type="table-fn"}
  A laboratory test performed on the donated blood may help me to evaluate my health                                      188              40.1[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   197       42.0[\#](#tfn7-ijgm-7-401){ref-type="table-fn"}   50                  10.7             26    5.5                                               8     1.7                                               10.9 (*P*=0.027)[\*](#tfn8-ijgm-7-401){ref-type="table-fn"}

**Notes:**

Positive attitude

statistically significant. Sex differences were measured by the χ^2^ test.

###### 

Knowledge and attitude percentage mean scores by some characteristics

  ----------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                 Knowledge percentage score mean ± SD                                Attitude percentage score mean ± SD
  ------------------------------ ------------------------------------------------------------------- -------------------------------------------------------------------
  Sex                                                                                                

   Male                          56.89±16.95                                                         76.45±12.12

   Female                        61.79±16.80\                                                        72.32±9.69\
                                 *t*=2.68; *P*=0.008[\*](#tfn10-ijgm-7-401){ref-type="table-fn"}\    *t*=3.70; *P*\<0.001[\*](#tfn10-ijgm-7-401){ref-type="table-fn"}\
                                 adj *P*=0.098                                                       adj *P*=0.001[\*](#tfn10-ijgm-7-401){ref-type="table-fn"}

  Age group                                                                                          

   \<30 years                    57.01±17.97                                                         75.71±12.42

   ≥30 years                     59.09±16.04\                                                        75.21±10.99\
                                 *t*=1.326; *P*=0.185\                                               *t*=0.46; *P=*0.644\
                                 adj *P*=0.668                                                       adj *P*=0.312

  Education level                                                                                    

   ≤ High school                 55.72±16.39                                                         75.86±11.23

   University                    60.90±17.38\                                                        74.96±12.26\
                                 *t*=3.321; *P=*0.001[\*](#tfn10-ijgm-7-401){ref-type="table-fn"}\   *t*=0.82; *P=*0.41\
                                 adj *P*=0.001[\*](#tfn10-ijgm-7-401){ref-type="table-fn"}           adj *P*=0.693

  Marital status                                                                                     

   Married                       59.45±15.55                                                         75.48±11.30

   Unmarried                     56.10±18.80\                                                        75.41±12.28\
                                 *t*=2.11; *P=*0.036[\*](#tfn10-ijgm-7-401){ref-type="table-fn"}\    *t*=0.06; *P=*0.952\
                                 adj *P*=0.194                                                       adj *P*=0.457

  History of blood transfusion                                                                       

   Yes                           61.10±15.76                                                         76.20±11.82

   No                            56.43±17.48\                                                        75.05±11.64\
                                 *t*=2.86; *P=*0.004[\*](#tfn10-ijgm-7-401){ref-type="table-fn"}\    *t*=1.014; *P=*0.311\
                                 adj *P*=0.021[\*](#tfn10-ijgm-7-401){ref-type="table-fn"}           adj *P*=0.112
  ----------------------------------------------------------------------------------------------------------------------------------------------------------------------

**Notes:** Every variable was adjusted for all other variables in the table.

Statistically significant.

**Abbreviations:** adj, adjusted; SD, standard deviation.

###### 

Significant predictors for blood donation frequency among the Saudi public

  Independent variables              *β*      SE      *t*     *P*
  ---------------------------------- -------- ------- ------- ---------------------------------------------------
  Sex (male =1)                      0.800    0.08    10.45   0.000[\*](#tfn12-ijgm-7-401){ref-type="table-fn"}
  Age group                          0.037    0.08    0.45    0.652
  Married versus unmarried           0.098    0.08    1.17    0.242
  University versus High School      0.070    0.06    1.10    0.274
  Total knowledge score percentage   0.005    0.002   2.59    0.010[\*](#tfn12-ijgm-7-401){ref-type="table-fn"}
  Total attitude score percentage    0.009    0.003   3.26    0.001[\*](#tfn12-ijgm-7-401){ref-type="table-fn"}
  History of blood transfusion       −0.087   0.06    −1.58   0.115
  Constant                           −0.927   0.23    −4.09   0.000

**Note:**

Statistically significant.

**Abbreviation:** SE, standard error.
