***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: BACKGROUND Cross-sectional studies on human hypertension have suggested an association between sodium intake and left ventricular hypertrophy ( LVH ) . METHODS AND RESULTS The effects on LVH of a nonpharmacological treatment program based mainly on sodium restriction were examined by serial echocardiography in a 12-month controlled , r and omized study that included 76 previously untreated subjects with uncomplicated mild-to-moderate hypertension . The mean daily sodium excretion of 38 subjects r and omized into the treatment group decreased from 195 + /- 95 to 94 + /- 73 mmol ( P < .001 ) at 6 months and to 109 + /- 74 mmol ( P < .001 ) at 12 months . This was accompanied by a weight decrease from 81.4 + /- 18.0 to 79.2 + /- 17.4 kg ( P < .001 ) at 6 months and to 80.6 + /- 17.5 kg ( NS ) at 12 months . The net blood pressure decrease ( difference in change from baseline between the treatment and control groups ) was 8.9 mm Hg ( P < .001 ) in systolic blood pressure and 6.5 mm Hg ( P < .001 ) in diastolic blood pressure during the first 6 months and 6.7 mm Hg ( P < .01 ) in systolic blood pressure and 3.8 mm Hg ( P < .01 ) in diastolic blood pressure during the last 6 months . After 12 months of sodium restriction , left ventricular mass ( LVM ) had decreased by 5.4 % ( from 238 + /- 63 to 225 + /- 51 g , P < .01 ) , and LVM index ( LVMI ) had decreased by 4.7 % ( from 123 + /- 26 to 117 + /- 22 g/m2 , P < .05 ) , whereas no changes occurred in these parameters in the control group . In treated subjects with baseline LVMI of more than the median value of 133 g/m2 in men and 107 g/m2 in women , LVM decreased by 8.6 % ( from 272 + /- 62 to 249 + /- 51 g , P < .01 ) , and LVMI decreased by 7.1 % ( from 140 + /- 23 to 130 + /- 22 g/m2 , P < .01 ) . LVM and LVMI remained unchanged in treated subjects with LVMI values equal to or less than the median . CONCLUSIONS Our data suggest that long-term nonpharmacological treatment with moderate sodium restriction decreases LVH 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 Background and Purpose — Despite the evidence for a positive association of dietary salt and blood pressure , the few prospect i ve studies that have assessed the association between dietary salt and stroke have reported inconsistent results . The purpose of this study was to examine the relation between sodium intake and death from stroke in a population -based cohort of Japanese men and women . Methods — In 1992 , usual diet including sodium intake was determined in 13 355 men and 15 724 women in Takayama City , Gifu , with the use of a vali date d food frequency question naire . Results — There were 269 stroke deaths ( 137 men and 132 women ) between baseline and 1999 . In men , the highest compared with the lowest tertile of sodium intake was significantly positively associated with death from total stroke after controlling for covariates ( hazard ratio [ HR ] ) , 2.33 ; 95 % CI , 1.23 to 4.45 ) . Significantly positive associations were also observed between sodium intake and death from ischemic stroke ( HR , 3.22 ; 95 % CI , 1.22 to 8.53 ) as well as death from intracerebral hemorrhage ( HR , 3.85 ; 95 % CI , 1.16 to 12.7 ) . A positive association between sodium intake and death from stroke in women was suggested , although the associations for total stroke and ischemic stroke were of borderline significance ( HR , 1.70 ; 95 % CI , 0.96 to 3.02 and HR , 2.10 ; 95 % CI , 0.96 to 4.62 , respectively ) . Conclusions — These prospect i ve data support the hypothesis that dietary salt increases the risk of death from stroke Hypertensive ( n=93 ) and normotensive ( n=39 ) white individuals were given a high sodium intake of ≈350 mmol/d for 5 days followed by a low sodium intake of 10 to 20 mmol/d for 5 days . With this acute and large reduction in salt intake , no significant change was seen in blood pressure in the normotensive individuals , but blood pressure decreased in the hypertensive individuals . Compared with normotensive subjects , hypertensive patients had a 7/7-mm Hg greater fall in blood pressure ( P < 0.05 for systolic and P < 0.01 for diastolic , adjusted for age ) , with similar changes in urinary sodium excretion . From the high-salt to low-salt diet , plasma renin activity rose from 0.90 to 5.99 ng · mL−1 · h−1 in normotensives , whereas in hypertensives it rose from 0.73 to only 3.14 ng · mL−1 · h−1 ( P < 0.05 between hypertensives and normotensives ) . Plasma aldosterone rose by 1396 pmol/L in normotensive subjects and by 511 pmol/L in hypertensive patients ( P < 0.05 ) . Significant inverse correlations were obtained for all subjects between the fall in blood pressure from the high-salt to low-salt diet and the rise in plasma renin activity and aldosterone that occurred in addition to the absolute level on the low-salt diet . These results demonstrate that the larger fall in blood pressure with an acute reduction in salt intake in hypertensives compared with normotensives is , at least in part , due to a less-responsive renin-angiotensin-aldosterone system in the hypertensive patients Evidence on the association between salt intake and  gastric cancer  is sparse , especially in prospect i ve studies . We conducted a population -based prospect i ve study in Japan , where the majority of men has been infected with Helicobacter pylori . A total of 18 684 men and 20 381 women aged 40–59 years who reported their dietary habits and did not report any serious disease at baseline were followed from 1990 to 2001 . A total of 486 cases , 358 men and 128 women , with histologically confirmed gastric cancer were documented among them . The quintile category of salt intake was dose-dependently associated with gastric cancer risk in men after adjusting for potential confounding factors ( P for trend < 0.001 ) , while a trend was not clear in women ( P for trend=0.48 ) . Although stratification by study area , with varied salt intake and gastric cancer incidence , attenuated the observed clear associations with salt and salted foods , the frequency categories of highly salted foods such as salted fish roe and salted fish preserves were strongly associated with the risk in both sexes . Restriction of salt and salted food intake is a practical strategy to prevent gastric cancer in areas with high risk A model programme for hypertension control in the community has been implemented in North Karelia , Finl and , since 1972 . The treatment status of the patients was improved and blood pressure levels were reduced during 1972 to 1977 . This improvement started to level off during 1977 to 1982 , although more than 10 % of the population aged 35 - 64 years were treated with antihypertensive drugs .  Several analyses were done to find out which dietary factors contributed to the blood pressure level and to its change in the community . The study material consisted of r and om sample s of the population aged 30 - 59 years in two counties in Eastern Finl and , who participated in the surveys in 1972 , 1977 and 1982 . The analyses confirmed that high BMI , high fat intake , alcohol drinking and high Na intake were associated significantly with blood pressure and also with its change both in the general population and in hypertensive persons . The high levels of these nutritional factors were also associated with unsatisfactory outcome of drug treatment in the hypertensive patients . Thus , it is likely that nutritional changes that can reduce the levels of BMI , the intake of fat , alcohol , and Na would contribute significantly both to primary prevention and to the effective treatment of elevated blood pressure in the community . In Eastern Finl and the levels of alcohol intake have increased both in men and women , BMI increased in men and decreased in women and serum cholesterol levels dropped both in men and women between 1972 to 1982 . The results of a community-based programme to reduce salt intake in North Karelia from 1979 to 1982 confirmed that Na intake level is high in Finl and . The North Karelia Salt Project showed that it is difficult to reduce salt intake at the community level during a three-year period . A slight reduction in  Na intake was seen only in women both in North Karelia and in the reference area . In men Na intake did not decrease . In conclusion our results suggest that primary prevention of hypertension at the community level is not easy and that a well conceived programme for a relatively long time period is needed The effect of a health education programme on salt reduction and blood pressure was studied in two matched rural communities in Portugal , each of about 800 adult inhabitants . Initial salt intake was high ( about 360 mmol/person/day ) and 30 % of persons were hypertensive ( DBP 95 mmHg or above ) . In the intervention community average blood pressure fell by 3.6/5.0 mmHg at one year and 5.0/5.1 mmHg at two years , due to a general distribution shift . In the control community diastolic pressures remained stable and systolic pressures rose . The difference in trends between the two communities was highly significant . There were also significant correlations within individuals in the intervention community between fall in blood pressure and fall in urinary sodium/creatinine ratio . At least in this high-intake population a fall in salt consumption seems to have caused an important fall in average blood pressure CONTEXT Dietary sodium is positively associated with blood pressure , and ecological and animal studies both have suggested that high dietary sodium intake increases stroke mortality . OBJECTIVE To examine the risk of cardiovascular disease associated with dietary sodium intake in overweight and nonoverweight persons . DESIGN Prospect i ve cohort study . SETTING The first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study , conducted in 1982 - 1984 , 1986 , 1987 , and 1992 . PARTICIPANTS Of those aged 25 to 74 years when the survey was conducted in 1971 -1975 ( 14407 participants ) , a total of 2688 overweight and 6797 nonoverweight persons were included in the analysis . MAIN OUTCOME MEASURES  Dietary sodium and energy intake  were estimated at baseline using a single 24-hour dietary recall method .  Incidence and mortality data for cardiovascular disease were obtained from medical records and death certificates . RESULTS For overweight and nonoverweight persons , over an average of 19 years of follow-up , the total number of documented cases were as follows : 680 stroke events ( 210 fatal ) , 1727 coronary heart disease events ( 614 fatal ) , 895 cardiovascular disease deaths , and 2486 deaths from all causes . Among overweight persons with an average energy intake of 7452 kJ , a 100 mmol higher sodium intake was associated with a 32 % increase ( relative risk [ RR ] , 1.32 ; 95 % confidence interval [ CI ] , 1.07 - 1.64 ; P = .01 ) in stroke incidence , 89 % increase ( RR , 1.89 ; 95 % CI , 1.31 - 2.74 ; P<.001 ) in stroke mortality , 44 % increase ( RR , 1.44 ; 95 % CI , 1.14 - 1.81 ; P = .00 
    Output:
    
REVIEW ERS ' CONCLUSIONS Our meta- analysis demonstrates that a modest reduction in salt intake for a duration of 4 or more weeks has a significant and , from a population viewpoint , important effect on blood pressure in both individuals with normal and elevated blood pressure .
These results support other evidence suggesting that a modest and long-term reduction in population salt intake could reduce strokes , heart attacks , and heart failure .
Furthermore , our meta- analysis demonstrates a correlation between the magnitude of salt reduction and the magnitude of blood pressure reduction .
Within the daily intake range of 3 to 12 g/day , the lower the salt intake achieved , the lower the blood pressure