Cost-effectiveness of vitamin therapy to lower plasma homocysteine levels for the prevention of coronary heart disease: effect of grain fortification and beyond.

CONTEXT: A high homocysteine level has been identified as an independent modifiable risk factor for coronary heart disease (CHD) events and death. Since January 1998, the US Food and Drug Administration has required that all enriched grain products contain 140 microg of folic acid per 100 g, a level considered to decrease homocysteine levels. OBJECTIVES: To examine the potential effect of grain fortification with folic acid on CHD events and to estimate the cost-effectiveness of additional vitamin supplementation (folic acid and cyanocobalamin) for CHD prevention. DESIGN AND SETTING: Cost-effectiveness analysis using the Coronary Heart Disease Policy Model, a validated, state-transition model of CHD events in adults aged 35 through 84 years. Data from the third National Health and Nutrition Examination Survey (NHANES III) were used to estimate age- and sex-specific differences in homocysteine levels. INTERVENTION: Hypothetical comparison between a diet that includes enriched grain products projected to increase folic acid intake by 100 microg/d with the same diet without folic acid fortification; and a comparison between vitamin therapy that consists of 1 mg of folic acid and 0.5 mg of cyanocobalamin and the diet that includes grains fortified with folic acid. MAIN OUTCOME MEASURES: Incidence of myocardial infarction and death from CHD, quality-adjusted life-years (QALYs) saved, and medical costs. RESULTS: Grain fortification with folic acid was predicted to decrease CHD events by 8% in women and 13% in men, with comparable reductions in CHD mortality. The model projected that, compared with grain fortification alone, treating all patients with known CHD with folic acid and cyanocobalamin over a 10-year period would result in 310 000 fewer deaths and lower costs. Over the same 10-year period, providing vitamin supplementation in addition to grain fortification to all men aged 45 years or older without known CHD was projected to save more than 300 000 QALYs, to save more than US $2 billion, and to be the preferred strategy. For women without CHD, the preferred vitamin supplementation strategy would be to treat all women older than 55 years, a strategy projected to save more than 140 000 QALYs over 10 years. CONCLUSIONS: Folic acid and cyanocobalamin supplementation may be cost-effective among many population subgroups and could have a major epidemiologic benefit for primary and secondary prevention of CHD if ongoing clinical trials confirm that homocysteine-lowering therapy decreases CHD event rates.

Relation of serum ascorbic acid to mortality among US adults.

PURPOSE: To examine the relation between serum ascorbic acid (SAA), a marker of dietary intake (including supplements), and cause-specific mortality. SUBJECTS AND METHODS: We analyzed data from a probability sample of 8,453 Americans age > or = 30 years at baseline enrolled in the Second National Health and Nutrition Examination Survey (NHANES II), who were followed for mortality endpoints. We calculated relative hazard ratios as measures of disease association comparing the mortality rates in three biologically relevant SAA categories. RESULTS: Participants with normal to high SAA levels had a marginally significant 21% to 25% decreased risk of fatal cardiovascular disease (CVD) (p for trend = 0.09) and a 25% to 29% decreased risk of all-cause mortality (p for trend <0.001) compared to participants with low levels. Because we determined that gender modified the association between SAA levels and cancer death, we analyzed these associations stratified by gender. Among men, normal to high SAA levels were associated with an approximately 30% decreased risk of cancer deaths, whereas such SAA levels were associated with an approximately two-fold increased risk of cancer deaths among women. This association among women persisted even after adjustment for baseline prevalent cancer and exclusion for early cancer death or exclusion for prevalent cancer. CONCLUSIONS: Low SAA levels were marginally associated with an increased risk of fatal CVD and significantly associated with an increased risk for all-cause mortality. Low SAA levels were also a risk factor for cancer death in men, but unexpectedly were associated with a decreased risk of cancer death in women. If the association between low SAA levels and all-cause mortality is causal, increasing the consumption of ascorbic acid, and thereby SAA levels, could decrease the risk of death among Americans with low ascorbic acid intakes.

Phytoestrogens and healthy aging: gaps in knowledge. A workshop report.

There is an increasing public interest in foods and dietary supplements containing phytoestrogens for the maintenance of health. A workshop was convened to assess evidence for the potential benefits of phytoestrogen-containing foods or supplements on diseases or conditions affecting older populations. Preclinical, clinical, and epidemiologic data on the cardiovascular system, various cancers, bone diseases, and menopausal symptoms were the focus of the discussions. Research on the basis of consumer food choices as well as a presentation from the FDA regarding approval of the use of soy foods to reduce the risk of cardiovascular disease were also presented. Based on the information presented, isoflavone-containing soy foods may have favorable effects on the cardiovascular system, but major knowledge gaps still exist regarding effects ofphytoestrogen supplements on bone diseases, various cancers, menopausal symptoms, and cognitive function.

What if Americans ate less fat? A quantitative estimate of the effect on mortality.

Americans consume an average of 37% of their energy intake as fat. Many authorities recommend restricting fat intake to 30% of energy intake to reduce the rates of coronary heart disease and perhaps of cancers of the breast, colon, and prostate. Based on the assumptions that underlie those recommendations, we estimated the effect of this dietary change on mortality. If all Americans restricted their intake of dietary fat by reducing consumption of saturated fat and accompanying dietary cholesterol, the corresponding reductions in serum cholesterol levels could reduce coronary heart disease mortality rates by 5% to 20%, depending on age. If the relationship between dietary fat and cancer is as strong as has been observed in some studies, the proportional effects on mortality from fat-related cancers could be even greater, although the absolute effects--given the lower mortality rates--would be smaller. Overall, if the assumptions are correct, about 42,000 of the 2.3 million deaths that would have occurred in adults each year in the United States could be deferred. This 2% benefit, equivalent to an increase in average life expectancy of 3 to 4 months, would accrue chiefly to people over the age of 65 years. If recent concerns about the possibly harmful effects of cholesterol lowering on mortality from noncardiovascular causes--which mainly affect younger persons--are valid, these relatively modest benefits would be overestimates of the actual effect.