***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: STUDY OBJECTIVE --The aim was to examine social and physical correlates of blood pressure in 15 year olds . DESIGN --This was the first , baseline , sweep of a longitudinal survey of 15 year olds based on a two stage stratified clustered r and om sample . SETTING --The Central Clydeside Conurbation , in the West of Scotl and . In 1981 this had a population of 1.7 million and a st and ardised mortality ratio ( relative to Scotl and as a whole ) of 109 . SUBJECTS -- A r and om sample of households containing 15 year olds were approached by Strathclyde Regional Council ; 70 % agreed to have their names passed on to the MRC ( 15 % refused , 10 % could not be contacted , and 5 % had moved ) . Of these 1177 , 11 % refused to participate , 3 % were not contactable/had moved , and 4 % did not provide full data . Complete blood pressure data are available for 959 15 year olds ( 464 males and 495 females ) . MEASUREMENTS AND MAIN RESULTS --Blood pressure , pulse rate , height , weight , and room temperature were measured by nurses in the subjects ' homes . Smoking , drinking , and frequency of vigorous exercise were self reported . Maternal height , birthweight , occupation of head of household , and housing tenure were reported by parents . After controlling for the other variables , systolic blood pressure was significantly associated with weight , pulse rate , and room temperature in males and with weight , pulse rate , housing tenure , smoking , and exercise in females . Diastolic blood pressure was associated with room temperature in males and with mother 's height , pulse rate , and housing tenure in females . Controlling for current weight , birthweight was inversely related to systolic blood pressure in males and positively associated in females , though in neither case were these associations statistically significant . CONCLUSIONS --In males , blood pressure was mainly related to anthropometric factors whereas in females it was additionally related to socioeconomic and behavioural variables . Although not reaching significance , the weight st and ardised relationship between birthweight and systolic blood pressure was consistent for males , but not females , with those reported by recent British studies of children and adults . The longitudinal design of this study will allow us to examine correlates of blood pressure in the same individuals as they reach social and physical maturity STUDY OBJECTIVE : To examine the relation between birth weight and blood pressure at 5 years in a cohort of South African children . DESIGN : Prospect i ve cohort study . PARTICIPANTS : 849 five year old children . SETTING : Soweto , a sprawling urban area close to Johannesburg , South Africa , which was a design ated residential area for people classified as " black " under apartheid legislation . MAIN RESULTS : Systolic blood pressure at 5 years was inversely related to birthweight ( r = -0.05 , p = 0.0007 ) , independent of current weight , height , gestational age , maternal age or socioeconomic status at 5 years . There was no relation between birth weight and diastolic blood pressure . After adjusting for current weight and height , there was a mean decline in systolic blood pressure of 3.4 mm Hg ( 95 % confidence intervals 1.4 , 5.3 mm Hg ) for every 1000 g increase in birth weight . CONCLUSIONS : These data from a disadvantaged urbanised community in Southern Africa extend the reported observations of an inverse relation between birth weight and systolic blood pressure . The study adds to the evidence that influences in fetal life and early childhood influence systolic blood pressure . Further research is required to assess whether efforts to reduce the incidence of low birthweight babies will attenuate the prevalence of hypertension in future generations This study aims to determine whether variables reflecting an adverse intrauterine environment are associated with  childhood blood pressure .  The authors conducted a secondary analysis of data from a prospect i ve cohort of children born to healthy , nulliparous women enrolled in a r and omized controlled trial . A total of 518 children were traced in 1995 - 1996 from 614 eligible children born in a clinic in Rosario , Argentina . The outcome was systolic blood pressure at 5 - 9 years . Hemoglobin during pregnancy was positively associated with children 's pressure . Other maternal characteristics during pregnancy ( blood pressure , smoking , weight gain , weight at 20 weeks ' gestation , and glycemia ) and size at birth ( birth weight , ponderal index , head circumference/length ratio , and small for gestational age ) were not associated with children 's pressure . Among children in the upper quartile of body mass index , there was a weak inverse correlation between birth weight and systolic pressure , and systolic pressure was 14.8 mmHg ( 95 percent confidence interval : 3.3 , 26.4 ) higher in low birth weight children than in others . The main predictors of childhood pressure were childhood body mass index and maternal pressure outside pregnancy . In this healthy population , the authors found weak support for an association between variables reflecting an adverse fetal environment and childhood blood pressure . Low birth weight was a risk factor for high blood pressure only in overweight children BACKGROUND Many studies have shown that low birth weight is associated with high blood pressure . The composition of the diet of pregnant women has also been found to affect blood pressure in their children . We assessed the effect of prenatal exposure to the Dutch famine of 1944 - 1945 , during which the caloric intake from protein , fat and carbohydrate was proportionally reduced , on blood pressures in adults now aged about 50 years . METHODS AND RESULTS We measured blood pressures at home and in the clinic among people born at term in one hospital in Amsterdam , The Netherl and s , between November 1 1943 and February 28 1947 , for whom we had detailed birth records .  Blood pressures of people exposed to famine during late ( n = 120 ) , mid-(n = 109 ) or early gestation ( n = 68 ) were compared with those of people born in the year before or conceived in the year after the famine ( unexposed subjects , n = 442 ) . No effect of prenatal exposure on systolic and diastolic blood pressure was observed . The mean systolic blood pressure taken in the clinic in those exposed in late gestation , and adjusted for sex and age , was 1.3 mmHg higher than in the unexposed group ( 95 % confidence interval -1.9 to 4.4 ) . The mean systolic blood pressure differed by -0.6 mmHg ( 95 % confidence interval -3.9 to 2.7 ) for those exposed in mid-gestation and -1.7 mmHg ( 95 % confidence interval -5.6 to 2.2 ) for those exposed in early gestation . People who were small at birth had higher blood pressures . A 1 kg increase in birth weight was associated with a decrease of 2.7 mmHg ( 95 % confidence interval 0.3 to 5.1 ) in systolic blood pressure . Analyses of blood pressures measured at home gave similar results . CONCLUSION High blood pressure was not linked to prenatal exposure to a balanced reduction of macronutrients in the maternal diet . However , it was linked to reduced fetal growth . We postulate that it might be the composition rather than the quantity of a pregnant woman 's diet that affects her child 's blood pressure in later life BACKGROUND Several studies have found a relation ship between small size at birth and high blood pressure ( HBP ) . However , this association has not been fully evaluated in adolescence . The aim of the present study was to evaluate the relation of  birth weight ( BW ) to BP in adolescence , controlling for factors related to BP , to extrauterine environment , and to maternal risk of fetal distress . METHODS In 1310 adolescents ( ages 12 - 14 years ) , r and omly selected from Turin school children , we evaluated BP , heart rate ( HR ) , weight , height , familial risk of hypertension , parental cultural level , BW , and maternal history of diseases during pregnancy .  The BW-BP association was tested by using multiple regression analysis and adjusting for the other variables mentioned above . The same analysis was done for the subgroup at high risk of fetal distress . RESULTS The association between BW and BP was negative but weak when we adjusted for all confounders (= -0.07 in males ; = -0.27 in females ) . The association was negative and became stronger after the inclusion of all confounders , particularly HR (= -3.92 ) , in the group of children at high risk of fetal distress . CONCLUSIONS Intrauterine environment , as reflected by BW , has little effect on BP in early adolescence without concomitant maternal diseases or environmental conditions leading to severe placental hypoperfusion OBJECTIVES To determine the association between birth weight and systolic blood pressure ( SBP ) in male adolescents at the age of 18 years . DESIGN A prospect i ve study by means of a register linkage between the Swedish Medical Birth Register and the national register for conscript testing before military service . METHODS From the birth registry we collected data on birth weight , gestational age , maternal age and parity for 149378 individuals . At conscript testing , subjects were given a physical examination , and weight , height , and mean blood pressure were recorded after 5 - 10 min rest . RESULTS Mean+/-SD birth weight was 3543+/-551 g after a mean of 39.7+/-2.0 gestational weeks . Mean+/-SD blood pressure at the conscript testing was 128.8+/-10.9/65.2+/-10.6 mmHg . SBP , but not diastolic blood pressure , differed significantly ( test for trend , P < 0.001 ) between birth weight strata ( deciles ) , with a higher SBP in strata with lower birth weight . A difference in birth weight of 1000 g decreased SBP by 0.8 mmHg . This was most pronounced in subjects with a rapid growth development ( n = 1057 ) , coming from the lowest decile of birth weight and reaching to the highest decile of body mass index , in a very consistent manner . The odds ratio for being in the top decile of SBP was 1.55 ( 95 % confidence interval 1.32 - 1.81 ) for this growth ' catch-up ' group compared with the rest of the cohort . CONCLUSIONS Birth weight was inversely associated with SBP in a large cohort of young men in their late teens . This supports the notion of a programming effect of fetal growth retardation in utero on haemodynamic regulation in early adult life In a retrospective survey , 487 research projects approved by the Central Oxford Research Ethics Committee between 1984 and 1987 , were studied for evidence of publication bias . As of May , 1990 , 285 of the studies had been analysed by the investigators , and 52 % of these had been published . Studies with statistically significant results were more likely to be published than those finding no difference between the study groups ( adjusted odds ratio [ OR ] 2.32 ; 95 % confidence interval [ Cl ] 1.25 - 4.28 ) . Studies with significant results were also more likely to lead to a greater number of publications and presentations and to be published in journals with a high citation impact factor . An increased likelihood of publication was also associated with a high rating by the investigator of the importance of the study results , and with increasing sample size . The tendency towards publication bias was greater with observational and laboratory-based experimental studies ( OR = 3.79 ; 95 % Cl = 1.47 - 9.76 ) than with r and omised clinical trials ( OR = 0.84 ; 95 % Cl = 0.34 - 2.09 ) . We have confirmed the presence of publication bias in a cohort of clinical research studies . These findings suggest that conclusions based only on a review of published data should be interpreted cautiously , especially for observational studies . Improved strategies are needed to identify the results of unpublished as well as published studies 
    Output:
    
This analysis strongly suggests , but does not prove , that publication bias is present when systematic ally examining the relationship between blood pressure and birth weight .
Controlling for publication bias lessens the apparent relationship between the regression coefficient and age of the study population