***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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    ***EXAMPLES*** 
    Input: Neurohypophysial hormones are thought to be involved in alterations in fluid balance during pregnancy and delivery . In the course of normal pregnancy intravascular volume is increased whereas sodium restriction is thought to reduce plasma volume and cardiac output . In the present study , we measured the effect of long-term severe sodium restriction on vasopressin ( AVP ) and oxytocin ( OT ) levels during normal pregnancy and after delivery . Fifty-nine healthy nulliparous women were r and omized either for a low sodium diet ( 20 mmol sodium daily ) or for a normal diet from week 12 of pregnancy onwards . Circulating plasma levels and urinary excretion of AVP and OT , their neurophysins ( Np-AVP and Np-OT ) and AVP bound to platelets were determined at regular intervals during pregnancy and after delivery . After completion of the study , women on a sodium-restricted diet were compared with control women on a normal diet using repeated measurement ANOVA with adjustment for potentially confounding variables . After r and omization , a reduction in urinary sodium excretion of , on average , 40 - 82 % was found . In general , no effect of sodium restriction could be demonstrated on the various parameters ( 0.53 < P < 0.98 ) with the exception of a significantly lower 24-h urinary AVP excretion by non-smokers with sodium restriction compared with non-smokers having a normal diet ( P = 0.018 ) . For all parameters , clear changes were found in the course of pregnancy and puerperium ( P < 0.0001 to P < 0.005 ) . Platelet-bound AVP decreased and Np-OT increased during pregnancy . After birth , free plasma AVP , platelet-bound AVP , OT , osmolality , sodium and potassium increased , while Np-AVP and Np-OT decreased . Although elevated Np-AVP and Np-OT levels during pregnancy seem to indicate increased release of neurohypophysial hormones , pregnancy up to 36 weeks of gestation is accompanied by low circulating AVP and OT levels . Long-term severe sodium restriction diminishes urinary AVP excretion in ( non-smoking ) pregnant women , without changing circulating levels of AVP and OT , despite the known reduction in circulating volume . The reduced circulating ( platelet-bound ) AVP levels during pregnancy , whether or not in combination with severe sodium restriction , support the absence of significant non-osmotic stimulation of AVP during pregnancy Sodium restriction can reduce blood pressure in hypertensive patients . The present study indicates that if hypertension is well controlled then the reemergence of hypertension can be decreased by the use of a reduced sodium intake . The present paper demonstrates that in such patients on a normal salt diet  , 90 % become hypertensive within 6 months while only 40 % of people on a reduced sodium diet  become hypertensive . It is proposed that a high sodium intake activates a number of amplifiers that causes a shift of the dose-response curve to sodium to the left and if not prevented or interrupted leads to the development of hypertension Background Decreasing salt consumption can prevent cardiovascular diseases ( CVD ) . Practically , it is difficult to promote people ’s awareness of daily salt intake and to change their eating habits in terms of reducing salt intake for better cardiovascular health . Health education programs visualizing daily dietary salt content and intake may promote lifestyle changes in patients at high risk of cardiovascular diseases . Methods / Design This is a cluster r and omized trial . A total of 800 high-CVD-risk patients attending diabetes and hypertension clinics at health centers in Muang District , Chiang Rai province , Thail and , will be studied with informed consent . A health center recruiting 100 participants is a cluster , the unit of r and omization . Eight clusters will be r and omized into intervention and control arms and followed up for 1 year . Within the intervention clusters the following will be undertaken : ( 1 )  salt content in the daily diet will be measured and shown to study participants ; ( 2 )  24-hour salt intake will be estimated in overnight-collected urine and the results shown to the participants ; ( 3 ) a dietician will assist small group health education classes in cooking meals with less salt . The primary outcome is blood pressure change at the 1-year follow-up . Secondary outcomes at the 1-year follow-up are estimated 24-hoursalt intake , incidence of CVD events and CVD death . The intention-to-treat analysis will be followed . Blood pressure and estimated 24-hour salt intake will be compared between intervention and control groups at the cluster and individual level at the 1-year follow-up . Clinical CVD events and deaths will be analyzed by time-event analysis . Retinal blood vessel calibers of CVD-risk patients will be assessed cross-sectionally . Behavioral change to reduce salt intake and the influencing factors will be determined by structured equation model ( SEM ) . Multilevel regression analyses will be applied . Finally , the cost effectiveness of the intervention will be analyzed . Discussion This study is unique as it will recruit the individuals most vulnerable to CVD morbidity and mortality by applying the general Framingham CVD risk scoring system . Dietary salt reduction will be applied as a prioritized , community level intervention for the prevention of CVD in a developing country . Trial registration IS RCT The aim of the present study was to evaluate the effects of a normal-sodium ( 120 mmol sodium ) diet compared with a low-sodium diet ( 80 mmol sodium ) on readmissions for CHF ( congestive heart failure ) during 180 days of follow-up in compensated patients with CHF . A total of 232 compensated CHF patients ( 88 female and 144 male ; New York Heart Association class II-IV ; 55 - 83 years of age , ejection fraction < 35 % and serum creatinine < 2 mg/dl ) were r and omized into two groups : group 1 contained 118 patients ( 45 females and 73 males ) receiving a normal-sodium diet plus oral furosemide [ 250 - 500 mg , b.i.d . ( twice a day ) ] ; and group 2 contained 114 patients ( 43 females and 71 males ) receiving a low-sodium diet plus oral furosemide ( 250 - 500 mg , b.i.d . ) . The treatment was given at 30 days after discharge and for 180 days , in association with a fluid intake of 1000 ml per day . Signs of CHF , body weight , blood pressure , heart rate , laboratory parameters , ECG , echocardiogram , levels of BNP ( brain natriuretic peptide ) and aldosterone levels , and PRA ( plasma renin activity ) were examined at baseline ( 30 days after discharge ) and after 180 days . The normal-sodium group had a significant reduction ( P<0.05 ) in readmissions . BNP values were lower in the normal-sodium group compared with the low sodium group ( 685+/-255 compared with 425+/-125 pg/ml respectively ; P<0.0001 ) . Significant ( P<0.0001 ) increases in aldosterone and PRA were observed in the low-sodium group during follow-up , whereas the normal-sodium group had a small significant reduction ( P=0.039 ) in aldosterone levels and no significant difference in PRA . After 180 days of follow-up , aldosterone levels and PRA were significantly ( P<0.0001 ) higher in the low-sodium group . The normal-sodium group had a lower incidence of rehospitalization during follow-up and a significant decrease in plasma BNP and aldosterone levels , and PRA . The results of the present study show that a normal-sodium diet improves outcome , and sodium depletion has detrimental renal and neurohormonal effects with worse clinical outcome in compensated CHF patients . Further studies are required to determine if this is due to a high dose of diuretic or the low-sodium diet The Hypertension Prevention Trial ( HPT ) was a r and omized , controlled , multicenter ( four clinics , four re source centers ) trial design ed to test the feasibility of achieving and sustaining dietary changes in the intake of calories , sodium , and potassium and to assess the effect of those changes on blood pressure in a normotensive population . The trial involved 841 men and women ( plus a test cohort of 78 ) who , at the first baseline ( BL ) examination , were in the age range of 25 - 49 years and had diastolic blood pressure ( DBP ) greater than or equal to 76 but less than 100 mm Hg ( average of two readings ) , and at the examination prior to r and omization ( BL 2 ) had DBP greater than or equal to 78 but less than 90 mm Hg ( also averaged ) . Participants were r and omly assigned to a control treatment group ( no dietary counseling ) or to one of four dietary treatment groups involving counseling design ed to reduce calorie intake , reduce sodium intake , reduce sodium and calorie intake , and reduce sodium and increase potassium intake . Dietary counseling was provided primarily in group setting s and was aim ed at changing participants ' shopping , cooking , and eating habits related to a design ated treatment assignment . The effect of dietary counseling was measured through changes in urinary excretion of sodium and potassium , changes in body weight , and changes in reported food intake based on 24-hour food records . Blood pressure changes during the 3-year course of followup were based on measurements taken at 6-month intervals from enrollment using a r and om-zero sphygmomanometer . This chapter provides a general description of the design and methods of the HPT and the underlying rationale for decisions affecting the design BACKGROUND The beneficial effects of potassium-enriched salt on blood pressure have been reported in a few short-term trials . The long-term effects of potassium-enriched salt on cardiovascular mortality have not been carefully studied . OBJECTIVE The objective was to examine the effects of potassium-enriched salt on cardiovascular disease ( CVD ) mortality and medical expenditures in elderly veterans . DESIGN Five kitchens of a veteran retirement home were r and omized into 2 groups ( experimental or control ) and veterans assigned to those kitchens were given either potassium-enriched salt ( experimental group ) or regular salt ( control group ) for approximately 31 mo . Information on death , health insurance cl aims , and date s that veterans moved in or out of the home was gathered . RESULTS Altogether , 1981 veterans , 768 in the experimental [ x ( + /-SD ) age : 74.8 + /- 7.1 y ] and 1213 in the control ( age : 74.9 + /- 6.7 y ) groups , were included in the analysis . The experimental group had better CVD survivorship than did the control group . The incidence of CVD-related deaths was 13.1 per 1000 persons ( 27 deaths in 2057 person-years ) and 20.5 per 1000 ( 66 deaths in 3218 person-years ) for the experimental and control groups , respectively . A significant reduction in CVD mortality ( age-adjusted hazard ratio : 0.59 ; 95 % CI : 0.37 , 0.95 ) was observed in the experimental group . Persons in the experimental group lived 0.3 - 0.90 y longer and spent significantly less ( approximately US Dollars 426/y ) in inpatient care for CVD than did the control group , after control for age and previous hospitalization expenditures . CONCLUSIONS This study showed a long-term beneficial effect on CVD mortality and medical expenditure associated with a switch from regular salt to potassium-enriched salt in a group of elderly veterans . The effect was likely due to a major increase in potassium and a moderate reduction in sodium intakes The Hypertension Prevention Trial ( HPT ) was a r and omized unmasked multicenter trial design ed to address questions concerning the feasibility and efficacy of dietary intervention in the primary prevention of hypertension . Participants in the diet treatments  were given counseling to achieve and sustain changes in calorie , sodium , and /or potassium intake . Diet composition , sodium and potassium excretion , and body weight were assessed for all participants at 6-mo intervals over 3 y. This paper provides information about extent and possible sources of bias in the dietary assessment methodology used in the HPT . Estimates of nutrient intake were derived from food records , urinalysis , and measurement of body weight . Reported potassium intake increased and sodium intake declined to a greater degree during the study than did potassium and sodium excretion . Our results indicate that repeated assessment s of diet , which depend upon participant recording , may not accurately represent usual diet in a dietary trial BACKGROUND Despite the reported benefits , weight loss is not always advised for older adults because some observational studies have associated weight loss with increased mortality . However , the distinction between intentional and unintentional weight loss is difficult to make in an observational context , so the effect of intentional weight loss on mortality may be clarified in the setting of a r and omized controlled trial . OBJECTIVE The objective was to determine the effect of intentional weight loss on all-cause mortality by using follow-up data from a r and omized trial completed in 1995 that included a weight-loss arm . DESIGN The Trial of Nonpharmacologic Intervention in the Elderly ( TONE ) used a 2 × 2 factorial design to determine the effect of dietary weight loss , sodium restriction , or both on blood 
    Output:
    
Despite collating more event data than previous systematic review s of r and omised controlled trials , there is insufficient power to confirm clinical ly important effects of dietary advice and salt substitution on cardiovascular mortality in normotensive or hypertensive population s. Our estimates of the clinical benefits from advice to reduce dietary salt are imprecise , but are larger than would be predicted from the small blood pressure reductions achieved .
Our findings do not support individual dietary advice as a means of restricting salt intake .