***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 
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    Input: CONTEXT Caffeine acutely increases blood pressure , but the association between habitual consumption of caffeinated beverages and incident hypertension is uncertain . OBJECTIVE To examine the association between caffeine intake and incident hypertension in women . DESIGN , SETTING , AND PARTICIPANTS Prospect i ve cohort study conducted in the Nurses ' Health Studies ( NHSs ) I and II of 155,594 US women free from physician-diagnosed hypertension followed up over 12 years ( 1990 - 1991 to 2002 - 2003 question naires ) .  Caffeine intake and possible confounders were ascertained from regularly administered question naires . We also tested the associations with types of caffeinated beverages . MAIN OUTCOME MEASURE Incident physician-diagnosed hypertension . RESULTS During follow-up , 19,541 incident cases of physician-diagnosed hypertension were reported in NHS I and 13,536 in NHS II . In both cohorts , no linear association between  caffeine  consumption and risk of incident hypertension was observed after multivariate adjustment ( NHS I , P for trend = .29 ; NHS II , P for trend = .53 ) . Using categorical analysis , an inverse U-shaped association between caffeine consumption and incident hypertension was found . Compared with participants in the lowest quintile of caffeine consumption , those in the third quintile had a 13 % and 12 % increased risk of hypertension , respectively ( 95 % confidence interval in NHS I , 8%-18 % ; in NHS II , 6%-18 % ) . When study ing individual classes of caffeinated beverages , habitual coffee consumption was not associated with increased risk of hypertension . By contrast , consumption of cola beverages was associated with an increased risk of hypertension , independent of whether it was sugared or diet cola ( P for trend < .001 ) . CONCLUSION No linear association between caffeine consumption and incident hypertension was found . Even though habitual coffee consumption was not associated with an increased risk of hypertension , consumption of sugared or diet cola was associated with it . Further research to eluci date the role of cola beverages in hypertension is warranted Carbonated beverages have been reported to increase fracture risk in children but the mechanism is unclear . The aim of this population -based case-control study was to investigate the association between soft drink and milk consumption , physical activity , bone mass , and upper limb fractures in children aged 9–16 years . A total of 206 fracture cases and 206 r and omly selected individually matched controls were studied . There were 47 h and fractures ; 128 wrist and forearm fractures , and 31 upper arm fractures . An interviewer-administered question naire was utilized to retrospectively assess last-year physical activity ( including television , computer , and video watching ) and to recall the average weekly consumption of milk , colas , and total carbonated drinks .  Bone mass at the spine , hip , and total body was assessed by dual-energy X-ray absorptiometry ( DXA ) and metacarpal morphometry . For total fractures , none of the above drink types was significantly different between cases and controls . For wrist and forearm fractures , there was a positive association between cola drink consumption and fracture risk ( OR 1.39/unit , 95 % CI : 1.01 , 1.91 ) . Cola consumption was significantly correlated with television , computer , and video watching ( r = 0.20 , P = 0.001 ) but not bone mineral density or milk drinks . After adjustment for television , computer , and video watching and bone mineral density , the association between cola drinks and fracture risk became nonsignificant ( OR 1.31/unit , 95 % CI : 0.94 , 1.83 ) . No association with other fracture sites was observed . In conclusion , cola , but not total carbonated beverage consumption , is associated with  increased wrist and forearm fracture risk in children . However , this association is not independent of other factors and appears to be mediated by television watching and bone mineral density but not by decreased milk intake BACKGROUND Intake of carbonated beverages has been associated with increased fracture risk in observational studies . The usual explanation given is that one or more of the beverage constituents increase urinary calcium . OBJECTIVE We assessed the short-term effects on urinary calcium excretion of carbonated beverages of various compositions . DESIGN An incomplete r and om block design was used to study 20 - 40-y-old women who customarily consumed > or = 680 mL carbonated beverages daily . Four carbonated beverages were tested : 2 with caffeine and 2 without . Two contained phosphoric acid as the acidulant and 2 contained citric acid . The study included one neutral control ( water ) and one positive control ( skim or chocolate milk ) . Serving size was 567 mL for the carbonated beverages and water and 340 mL for the milks . Beverages were consumed with a light breakfast after an overnight fast ; no other foods were ingested until urine collection was complete . pH , titratable and total acidity , sodium , creatinine , and calcium were measured in 2-h ( morning ) fasting and 5-h postbeverage urine specimens . RESULTS Relative to water , urinary calcium rose significantly only with the milks and the 2 caffeine-containing beverages . The excess calciuria was approximately 0.25 mmol , about the same as previously reported for caffeine alone . Phosphoric acid without caffeine produced no excess calciuria ; nor did it augment the calciuria of caffeine . CONCLUSIONS The excess calciuria associated with consumption of carbonated beverages is confined to caffeinated beverages . Acidulant type has no acute effect . Because the caffeine effect is known to be compensated for by reduced calciuria later in the day , we conclude that the net effect of carbonated beverage constituents on calcium economy is negligible . The skeletal effects of carbonated beverage consumption are likely due primarily to milk displacement To examine whether artificial sweeteners aid in the control of long-term food intake and body weight , we gave free-living , normal-weight subjects 1150 g soda sweetened with aspartame ( APM ) or high-fructose corn syrup ( HFCS ) per day . Relative to when no soda was given , drinking APM-sweetened soda for 3 wk significantly reduced calorie intake of both females ( n = 9 ) and males ( n = 21 ) and decreased the body weight of males but not of females . However , drinking HFCS-sweetened soda for 3 wk significantly increased the calorie intake and body weight of both sexes . Ingesting either type of soda reduced intake of sugar from the diet without affecting intake of other nutrients . Drinking large volumes of APM-sweetened soda , in contrast to drinking HFCS-sweetened soda , reduces sugar intake and thus may facilitate the control of calorie intake and body weight BACKGROUND High consumption of sugar-sweetened drinks has been associated with  weight gain and obesity in the United States . This trend may also be affecting population s with different eating patterns who increasingly are adopting typical US dietary patterns . OBJECTIVE We assessed whether the consumption of sweetened drinks and other food items increased the likelihood of weight gain in a Mediterranean population . DESIGN This was a prospect i ve cohort analysis of 7194 men and women with a mean age of 41 y who were followed-up for a median of 28.5 mo with mailed question naires . Dietary exposure was assessed with a previously vali date d semiquantitative food-frequency question naire . RESULTS During follow-up , we observed that 49.5 % of the participants increased their weight ( x weight gain : 0.64 kg ; 95 % CI : 0.55 , 0.73 kg ) . In the participants who had gained > or =3 kg in the 5 y before baseline , the adjusted odds ratio of subsequent weight gain for the fifth quintile compared with the first quintile of sugar-sweetened soft drink consumption was 1.6 ( 95 % CI : 1.2 , 2.1 ; P for trend = 0.02 ) . This association was absent in the participants who had not gained weight in the 5-y period before baseline . The consumption of hamburgers , pizza , and sausages ( as a proxy for fast-food consumption ) was also independently associated with weight gain ( adjusted odds ratio for the fifth compared with the first quintile = 1.2 ; 95 % CI : 1.0 , 1.4 ; P for trend = 0.05 ) . We also found a significant , but weaker , association between weight gain and both red meat and sweetened fruit juice consumption . CONCLUSION In a Mediterranean cohort , particularly in the participants who had already gained weight , an increased consumption of sugar-sweetened soft drinks and of hamburgers , pizza , and sausages was associated with a higher risk of additional subsequent weight gain Patients with kidney stones are routinely advised to increase their fluid intake to decrease the risk of stone recurrence . However , there has been no detailed examination to determine whether the effect on recurrence varies by the type of beverage consumed . The authors conducted a prospect i ve study of the relation between the intake of 21 different beverages and the risk of symptomatic kidney stones in a cohort of 45,289 men , 40 - 75 years of age , who had no history of kidney stones .  Beverage use and other dietary information was measured by means of a semiquantitative food frequency question naire in 1986 . During 6 years of follow-up ( 242,100 person-years ) , 753 incident cases of kidney stones were documented . After adjusting simultaneously for age , dietary intake of calcium , animal protein and potassium , thiazide use , geographic region , profession , and total fluid intake , consumption of specific beverages significantly added to the prediction of kidney stone risk ( p < 0.001 ) . After mutually adjusting for the intake of other beverages , the risk of stone formation decreased by the following amount for each 240-ml ( 8-oz ) serving consumed daily : caffeinated coffee , 10 % ( 95 % confidence interval 4 - 15 % ) ; decaffeinated coffee , 10 % ( 3 - 16 % ) ; tea , 14 % ( 5 - 22 % ) ; beer , 21 % ( 12 - 30 % ) ; and wine , 39 % ( 10 - 58 % ) . For each 240-ml serving consumed daily , the risk of stone formation increased by 35 % ( 4 - 75 % ) for apple juice and 37 % ( 1 - 85 % ) for grapefruit juice . The authors conclude that beverage type may have an effect on stone formation that involves more than additional fluid intake alone OBJECTIVE To determine if dietary calcium was negatively related to children 's body fat ( BF )  , if BF indexes and calcium intakes changed over time , and to identify variables related to BF and calcium intake . DESIGN Percent BF and kg BF were assessed by dual energy x-ray absorptiometry ( DEXA ) in 8-year-old children . In a prospect i ve design , height , weight , dietary intakes , and related variables were monitored longitudinally from ages 2 months to 8 years during in-home interviews . SUBJECTS Fifty-two white children , ( n=25 boys , 27 girls ) participated in a longitudinal study with their mothers . At 8 years of age , mean BMI was 17.3+/-2.1 ( st and ard deviation ) for boys and 17.1+/-2.5 for girls . ANALYSES Regression analysis of all variables , followed by further regression analysis on selected models . RESULTS At 8 years , percent BF was 22.7+/-6.7 for boys and 26.2+/-7.9 for girls , as assessed by DEXA . Dietary calcium ( mg ) and polyunsaturated fat intake ( g ) were negatively related to percent BF ( P=.02 to.04 ) in 3 statistical models , which predicted 28 % to 34 % of the variability in BF among children . Variables positively associated with percent BF were total dietary fat ( g ) or saturated fat ( g ) , female gender , sedentary activity ( hours/day ) , father 's BMI , and mothers ' percent BF . Calcium intakes were significantly correlated over time . Dietary variety was positively related to calcium intake , and intakes of carbonated beverages and other sweetened beverages were negatively related . APPLICATIONS/ CONCLUSIONS Children should be strongly encouraged to regularly include calcium-rich foods and beverages in their diets BACKGROUND The rising prevalence of obesity in children has been linked in part to the consumption of sugar-sweetened drinks . Our aim was to examine this relation . METHODS We enrolled 548 ethnically diverse schoolchildren ( age 11.7 years , SD 0.8 ) from public schools in four Massachusetts communities , and studied them prospect ively for 19 months from October , 1995 , to May , 1997 . We examined the association between baseline and change in consumption of sugar-sweetened drinks ( the independent variables ) , and difference in measures of obesity , with linear and logistic regression analyses adjusted for potentially confounding variables and clustering of results within schools . FINDINGS For each additional serving of sugar-sweetened drink consumed , both body mass index ( BMI ) ( mean 0.24 kg/m2 ; 95 % CI 0.10 - 0.39 ; p= 
    Output:
    
We found clear associations of soft drink intake with increased energy intake and body weight .
Soft drink intake also was associated with lower intakes of milk , calcium , and other nutrients and with an increased risk of several medical problems ( e.g. , diabetes ) .
Study design significantly influenced results : larger effect sizes were observed in studies with stronger methods ( longitudinal and experimental vs cross-sectional studies ) .
Finally , studies funded by the food industry reported significantly smaller effects than did non-industry-funded studies .