***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: A r and omized crossover trial on the effect of salt restriction on blood pressure was carried out involving 124 adolescents ( mean age 16 years ) .  Dietary sodium was reduced from approximately 110 to 45 mEq/24 h for a period of 24 days . Blood pressure was non-significantly lower at the end of the experimental diet for all participants . A slight ( 0.7 kg ) , yet statistically significant fall in weight was observed ( P less than 0.05 ) . Subgroup analysis demonstrated that participants whose body mass index was below the median had a statistically significant fall in systolic blood pressure ( P less than 0.05 ) ; fall in weight and increase in heart rate were also more pronounced in the less obese individuals . It would appear that moderate sodium reduction does not have an overall short-term effect on blood pressure in normotensive adolescents . However , body size as reflected in body mass index may influence blood pressure response to sodium reduction The aim of this study was to assess the relation between blood pressure ( BP ) and arterial compliance in a healthy sample of young adults . School children ( aged 10 to 14 years at entry ) were surveyed in 1977 to 1978 , and 1,207 were followed once to twice yearly until age 23 years .  Arterial compliance was measured in 179 adults at the last follow-up visit . The sample included individuals in the upper tertile of systolic BP during the last three follow-up visits and race- and sex-matched individuals in the lower two tertiles . We obtained radial artery waveforms using a calibrated tonometer device and characterized waveform morphology to determine large artery ( C1 ) and oscillatory ( C2 ) compliance .  Blood pressure  was measured using r and om zero sphygmomanometers . The mean and st and ard deviation of C1 was 2.13 + /- 0.59 mL/mm Hg and of C2 was 0.083 + /- 0.02 mL/mm Hg . Systolic BP was inversely related to C1 ( P < .001 ) and C2 ( P < .01 ) after adjustment for gender , height , weight , insulin , and HDL and LDL cholesterol . After adjustment , a 1 SD change in systolic BP was associated with a -0.30 mL/mm Hg change in C1 and a -.008 mL/mm Hg change in C2 . Data from the Minnesota Children 's Blood Pressure Study indicate that systolic BP is inversely related to arterial compliance , particularly C1 ( the large artery , or capacitive compliance ) To examine the long-term effects of weight loss and dietary sodium reduction on the incidence of hypertension , we studied 181 men and women who participated in the Trials of Hypertension Prevention , phase 1 , in Baltimore , Md. At baseline ( 1987 to 1988 ) , subjects were 30 to 54 years old and had a diastolic blood pressure ( BP ) of 80 to 89 mm Hg and systolic BP < 160 mm Hg . They were r and omly assigned to one of two 18-month lifestyle modification interventions aim ed at either weight loss or dietary sodium reduction or to a usual care control group . At the posttrial follow-up ( 1994 to 1995 ) , BP was measured by blinded observers who used a r and om-zero sphygmomanometer . Incident hypertension was defined as systolic BP > or = 160 mm Hg and /or diastolic BP > or = 90 mm Hg and /or treatment with antihypertensive medication during follow-up . Body weight and urinary sodium were not significantly different among the groups at the posttrial follow-up . After 7 years of follow-up , the incidence of hypertension was 18.9 % in the weight loss group and 40.5 % in its control group and 22.4 % in the sodium reduction group and 32.9 % in its control group . In logistic regression analysis adjusted for baseline age , gender , race , physical activity , alcohol consumption , education , body weight , systolic BP , and urinary sodium excretion , the odds of hypertension was reduced by 77 % ( odds ratio 0.23 ; 95 % confidence interval 0.07 to 0.76 ; P=0.02 ) in the weight loss group and by 35 % ( odds ratio 0.65 ; 95 % confidence interval 0.25 to 1.69 ; P=0.37 ) in the sodium reduction group compared with their control groups . These results indicate that lifestyle modification such as weight loss may be effective in long-term primary prevention of hypertension The roots of essential hypertension extend back into the first two decades of life , suggesting that effective intervention during those years may lead to a reduction in the incidence of adult hypertension . Decreasing the dietary sodium/potassium ratio offers a potentially effective approach to blood pressure reduction . This study tested the feasibility of 3-year sodium reduction or potassium supplementation in adolescents and the effect of these interventions on the rate of rise of blood pressure during adolescence . After 19,452 5th to 8th grade students were screened , 210 from the upper 15 percentiles of blood pressure distribution ( 105 boys , 105 girls ) were r and omly assigned to one of three groups : low sodium diet ( 70 mmol sodium intake per day ) , potassium chloride supplementation ( normal diet plus 1 mmol/kg potassium chloride per day ) , or placebo ( normal diet plus placebo capsule ) . Capsules for the potassium chloride and placebo groups were administered in a double blind protocol . Blood pressure was measured every 3 months for 3 years . The effect of the intervention was determined by comparing the rate of rise ( slope ) of blood pressure among the groups using a r and om-coefficient growth curve model . The boys groups and the girls placebo group had similar positive blood pressure slopes that were significantly different from zero . The girls low sodium group had a slightly negative slope ( significantly lower than the slope of the girls placebo group ) , and the girls potassium group had a slightly positive slope . Both of these slopes were not significantly different from zero and were significantly lower than the slopes of the respective boys groups . ( ABSTRACT TRUNCATED AT 250 WORDS In 1980 , a r and omized trial was conducted among 476 Dutch newborn infants to study the effect of a low or normal sodium diet on blood pressure during the first 6 months of life . At the end of the trial , systolic blood pressure in the low sodium group ( n = 231 ) was 2.1 mm Hg lower than in the control group ( n = 245 ) . To investigate whether contrasting levels of sodium intake in infancy are associated with blood pressure differences in adolescence , we measured blood pressure in 167 children from the original cohort ( 35 % ) after 15 years of follow-up . We assessed the differences in systolic and diastolic blood pressure levels between the diet groups using a multivariate regression model with adjustment for potential confounders . The adjusted systolic blood pressure at follow-up was 3.6 mm Hg lower ( 95 % confidence interval , -6.6 to -0.5 ) and the diastolic pressure was 2.2 mm Hg lower ( 95 % confidence interval , -4.5 to 0.2 ) in children who had been assigned to the low sodium group ( n = 71 ) compared with the control group ( n = 96 ) . These findings suggest that sodium intake in infancy may be important in relation to blood pressure later in life The position of both the body and the arm during indirect blood pressure ( BP ) measurement is often neglected . The aim of the present study was to test the influence of the position of the patient on BP readings : ( 1 ) sitting with the arms supported precisely at the right atrium level and ( 2 ) supine : ( a ) with the arms precisely at the right atrium level and ( b ) with the arms on the examination bed . In a first group of 57 hypertensive patients , two sessions of BP and heart rate ( HR ) measurements were performed in two positions : sitting and supine with the arms supported precisely at right atrium level in both positions . BP  was measured simultaneously at both arms , with a Hawksley R and om Zero sphygmomanometer at the right arm , and with an automated oscillometric device ( Bosomat ) at the left arm . BP and HR readings obtained in the two positions were then compared . In a second group of 25 normo- and hypertensive persons , two sessions of BP and HR readings were performed in supine with the arms in two different arm positions : ( a ) the arm placed precisely at right atrium level and ( b ) the other arm on the examination bed . The measurements were performed at both arms with two automated devices ( Bosomat ) . The readings taken in the two positions were compared . Both systolic BP ( SBP ; by 9.5±9.0 ( st and ard deviation , s.d . ) ; right arm ) and diastolic BP ( DBP ; by 4.8±6.0 mmHg ; right arm ) were significantly higher in the supine than in the sitting position . When the two different arm positions ( body continously supine ) were compared in the second part of the study , significantly higher SBP ( by 4.6±6.1 mmHg ) and DBP ( by 3.9±2.8 mmHg ) were obtained when the arm of the patient was placed on the bed ( below the right atrium level ) , than when the arm was placed at the level of the right atrium . BP readings in sitting and supine positions are not the same . When according to guidelines the arm of the patient is meticulously placed at the right atrium level in both positions , the difference is even greater than when the arm rests on the desk or on the arm support of the chair . Moreover , in the supine position small but significant differences in BP are measured between arm on a 5 cm-high pillow and arm on the bed . In every study reporting BP values , the position of both the body and especially the arm should be precisely mentioned The relationship between sodium intake and blood pressure in adolescents was examined in a dietary intervention study . One hundred schoolchildren aged 11 - 14 years and representing the top , middle and bottom deciles of the blood pressure range completed a crossover protocol requiring them to raise and lower their sodium intake for alternate periods of 4 weeks . Blood pressure and urinary sodium excretion were assessed weekly and diet diaries were recorded at the end of each 4-week diet period . Diet-diary analysis confirmed that sodium intake was selectively affected by the intervention . Estimates of average urinary sodium excretion at the end of each diet period differed by more than 80 mmol/day . However , there was no significant change of either systolic or diastolic blood pressure , measured supine in the whole study group , in either sex or in any of the sub-groups , even in those children representing the highest blood pressure decile . Furthermore , the blood pressure changes seen in individuals during the crossover did not correlate with their changes in sodium excretion . This lack of effect of sodium on blood pressure is consistent with other dietary intervention studies in children and supports the hypothesis that the sodium sensitivity of blood pressure is age-related . We conclude that dietary sodium restriction alone has little potential for lowering blood pressure at an early age , even in children with higher than average blood pressure OBJECTIVE This study examined the impact of the Transcendental Meditation ( TM ) program on cardiovascular ( CV ) reactivity in adolescents with high normal BP . METHOD Thirty-five adolescents [ 34 African Americans ( AAs ) , 1 Caucasian American ( CA ) ; ages 15 - 18 years ] with resting systolic blood pressure ( SBP ) between the 85th and 95th percentile for their age and gender on three consecutive occasions , were r and omly assigned to either TM ( n=17 ) or health education control ( CTL , n=18 ) groups . The TM group engaged in 15-min meditation twice each day for 2 months including sessions during school lunch break . Primary CV outcome measures were changes in blood pressure ( BP ) , heart rate ( HR ) , and cardiac output ( CO ) at rest and in response to two laboratory stressors , a simulated car driving stressor and an interpersonal social stressor interview . RESULTS The TM group exhibited greater decreases in resting SBP ( P<.03 ) from pre- to postintervention , compared to the CTL group . The TM group exhibited greater decreases from pre- to postintervention in SBP , HR , and CO reactivity ( P's<.03 ) to the simulated car driving stressor , and in SBP reactivity ( P<.03 ) to the social stressor interview . CONCLUSION The TM program appears to have a beneficial impact upon CV functioning at rest and during acute laboratory stress in adolescents at-risk for hypertension Delineating the role that diet plays in  blood pressure levels in children is important for guiding dietary recommendations for the prevention of hypertension . The purpose of this study was to investigate relationships between dietary nutrients and  blood pressure in children . Data were analyzed from 662 participants in the Dietary Intervention Study in Children who had elevated low-density lipoprotein cholesterol and were aged 8 to 11 years at baseline . Three 24-hour dietary recalls , systolic pressure , diastolic pressure , height , and weight were obtained at baseline , 1 year , and 3 years . Nutrients analyzed were the micronutrients calcium , magnesium , and potassium ; the macronutrients protein , carbohydrates , total fat , saturated fat , polyunsaturated fat , and monounsaturated fat ; dietary cholesterol ; and total dietary fiber . Baseline and 3-year longitudinal relationships were examined through multivariate models on diastolic and systolic pressures separately , controlling for height , weight , 
    Output:
    
It is important to emphasize that the decision to exclude overweight and obese children from the determination of reference points has led to BP cutoffs that were lower than those in the tables we had been using so far .