Invited commentary: a further look at dietary questionnaire validation.
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Diet Records↗
Biomedical subjects
W Willett
Publications and source records attributed to W Willett.
Assessment of questionnaire validity for measuring total fat intake using plasma lipid levels as criteria.
The validation of dietary total fat measurements has been elusive because no specific biomarker exists. In metabolic studies with controlled diets, plasma fasting triglyceride levels are reduced with higher fat intake and can thus serve as an "alloyed gold" standard. Participants in this cross-sectional analysis were 269 men aged 47-83 years from the Health Professionals Follow-up Study who completed a semiquantitative food frequency questionnaire and provided fasting blood specimens in 1994. In a multiple regression analysis adjusted for age; smoking; alcohol consumption; physical activity; body mass index; and intakes of protein, dietary fiber, and total energy, total fat intake was inversely associated with fasting triglycerides (for a fat increase of 1% of energy, triglyceride levels were lower by 2.5% (95% confidence interval: -3.7 to -1.3%, p = 0.0002)). For reported fat intakes of 20% or less of energy, the geometric mean fasting triglyceride level was 179, and for more than 40% of energy, it was 102 mg/dl. In addition, as predicted by metabolic studies, the inverse association between dietary fat and fasting triglyceride level was much stronger among overweight men than among men with a BMI of less than 25. These data provide additional evidence that informative measurements of dietary fat can be obtained by carefully constructed food frequency questionnaires.
Adult↗
Milk intake, circulating levels of insulin-like growth factor-I, and risk of colorectal cancer in men.
BACKGROUND: Milk and dietary calcium may have antiproliferative effects against colorectal cancer, but milk intake also raises serum levels of insulin-like growth factor-I (IGF-I). A high ratio of IGF-I to IGF-binding protein-3 (IGFBP-3) has been linked to an increased risk of colorectal cancer. METHODS: In a case-control study nested in the Physicians' Health Study, plasma samples were collected from the period 1982 through 1983 from 14 916 men, aged 40-84 years, who also answered dietary questionnaires. Circulating levels of IGF-I and IGFBP-3 were assayed among 193 men who developed colorectal cancer during 13 years of follow-up and 318 age- and smoking-matched cancer-free control men. Conditional logistic regression was used to assess relative risks (RRs) of colorectal cancer for tertiles of IGF-I/IGFBP-3 and dietary factors. Statistical tests were two-sided. RESULTS: Overall, there was a moderate but statistically nonsignificant inverse association between intake of low-fat milk or calcium from dairy food and colorectal cancer risk. Intake of dairy food (especially low-fat milk) was also positively and moderately associated with plasma levels of IGF-I, IGFBP-3, and IGF-I/IGFBP-3 among control men. We observed a statistically significant interaction between low-fat milk intake and IGF-I/IGFBP-3 in association with risk of colorectal cancer (P(interaction) =.03). Nondrinkers with IGF-I/IGFBP-3 in the highest tertile had a threefold higher risk than nondrinkers with IGF-I/IGFBP-3 in the lowest tertile (RR = 3.05; 95% confidence interval [CI] = 1.29 to 7.24), but no such increase was seen among frequent low-fat milk drinkers (RR = 1.05; 95% CI = 0.41 to 2.69). Conversely, among men with high IGF-I/IGFBP-3, frequent low-fat milk drinkers had a 60% lower risk (95% CI = 0.17 to 0.87; P(trend) =.02) than nondrinkers. CONCLUSION: Intake of dairy products was associated with a modest increase in circulating IGF-I levels, but intake of low-fat milk was associated with lower risk of colorectal cancer, particularly among individuals with high IGF-I/IGFBP-3. This subpopulation, which is at increased risk of colorectal cancer, might benefit the most from specific dietary intervention.
Adult↗
Dietary fat and risk for advanced age-related macular degeneration.
OBJECTIVE: To evaluate the relationship between intake of total and specific types of fat and risk for advanced age-related macular degeneration (AMD), the leading cause of irreversible blindness in adults. DESIGN: A multicenter eye disease case-control study. SETTING: Five US clinical ophthalmology centers. PATIENTS: Case subjects included 349 individuals (age range, 55-80 years) with the advanced, neovascular stage of AMD diagnosed within 1 year of their enrollment into the study who resided near a participating clinical center. Control subjects included 504 individuals without AMD but with other ocular diseases. Controls were from the same geographic areas as cases and were frequency-matched to cases by age and sex. MAIN OUTCOME MEASURES: Relative risk for AMD according to level of fat intake, controlling for cigarette smoking and other risk factors. RESULTS: Higher vegetable fat consumption was associated with an elevated risk for AMD. After adjusting for age, sex, education, cigarette smoking, and other risk factors, the odds ratio (OR) was 2.22 (95% confidence interval [CI], 1.32-3.74) for persons in the highest vs those in the lowest quintiles of intake (P for trend,.007). The risk for AMD was also significantly elevated for the highest vs lowest quintiles of intake of monounsaturated (OR, 1.71) and polyunsaturated (OR, 1.86) fats (Ps for trend,.03 and.03, respectively). Higher consumption of linoleic acid was also associated with a higher risk for AMD (P for trend,.02). Higher intake of omega-3 fatty acids was associated with a lower risk for AMD among individuals consuming diets low in linoleic acid, an omega-6 fatty acid (P for trend,.05; P for continuous variable,.03). Similarly, higher frequency of fish intake tended to reduce risk for AMD when the diet was low in linoleic acid (P for trend,.05). Conversely, neither omega-3 fatty acids nor fish intake were related to risk for AMD among people with high levels of linoleic acid intake. CONCLUSION: Higher intake of specific types of fat--including vegetable, monounsaturated, and polyunsaturated fats and linoleic acid--rather than total fat intake may be associated with a greater risk for advanced AMD. Diets high in omega-3 fatty acids and fish were inversely associated with risk for AMD when intake of linoleic acid was low.
Aged↗
Commentary: Dietary diaries versus food frequency questionnaires-a case of undigestible data.
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Diet Records↗
Lower prostate cancer risk in men with elevated plasma lycopene levels: results of a prospective analysis.
Dietary consumption of the carotenoid lycopene (mostly from tomato products) has been associated with a lower risk of prostate cancer. Evidence relating other carotenoids, tocopherols, and retinol to prostate cancer risk has been equivocal. This prospective study was designed to examine the relationship between plasma concentrations of several major antioxidants and risk of prostate cancer. We conducted a nested case-control study using plasma samples obtained in 1982 from healthy men enrolled in the Physicians' Health Study, a randomized, placebo-controlled trial of aspirin and beta-carotene. Subjects included 578 men who developed prostate cancer within 13 years of follow-up and 1294 age- and smoking status-matched controls. We quantified the five major plasma carotenoid peaks (alpha- and beta-carotene, beta-cryptoxanthin, lutein, and lycopene) plus alpha- and gamma-tocopherol and retinol using high-performance liquid chromatography. Results for plasma beta-carotene are reported separately. Odds ratios (ORs), 95% confidence intervals (Cls), and Ps for trend were calculated for each quintile of plasma antioxidant using logistic regression models that allowed for adjustment of potential confounders and estimation of effect modification by assignment to either active beta-carotene or placebo in the trial. Lycopene was the only antioxidant found at significantly lower mean levels in cases than in matched controls (P = 0.04 for all cases). The ORs for all prostate cancers declined slightly with increasing quintile of plasma lycopene (5th quintile OR = 0.75, 95% CI = 0.54-1.06; P, trend = 0.12); there was a stronger inverse association for aggressive prostate cancers (5th quintile OR = 0.56, 95% CI = 0.34-0.91; P, trend = 0.05). In the placebo group, plasma lycopene was very strongly related to lower prostate cancer risk (5th quintile OR = 0.40; P, trend = 0.006 for aggressive cancer), whereas there was no evidence for a trend among those assigned to beta-carotene supplements. However, in the beta-carotene group, prostate cancer risk was reduced in each lycopene quintile relative to men with low lycopene and placebo. The only other notable association was a reduced risk of aggressive cancer with higher alpha-tocopherol levels that was not statistically significant. None of the associations for lycopene were confounded by age, smoking, body mass index, exercise, alcohol, multivitamin use, or plasma total cholesterol level. These results concur with a recent prospective dietary analysis, which identified lycopene as the carotenoid with the clearest inverse relation to the development of prostate cancer. The inverse association was particularly apparent for aggressive cancer and for men not consuming beta-carotene supplements. For men with low lycopene, beta-carotene supplements were associated with risk reductions comparable to those observed with high lycopene. These data provide further evidence that increased consumption of tomato products and other lycopene-containing foods might reduce the occurrence or progression of prostate cancer.
Adult↗
Dietary fat and breast cancer.
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Breast Neoplasms↗
Exposure to breast milk in infancy and adult breast cancer risk.
BACKGROUND: There is considerable interest in the possibility of an infectious etiology for human breast cancer. Although studies have shown that certain strains of mice transmit mammary tumor virus via breast milk, few epidemiologic studies have addressed this topic in humans. METHODS: We evaluated the relationship between having been breast-fed as an infant and breast cancer risk among 8299 women who participated in a population-based, case-control study of breast cancer in women aged 50 years or more. Case women were identified through cancer registries in three states (Massachusetts, New Hampshire, and Wisconsin); control women were identified through statewide driver's license lists (age <65 years) or Medicare lists (ages 65-79 years). Information on epidemiologic risk factors was obtained through telephone interview. We used multiple logistic regression to assess having been breast-fed and maternal history of breast cancer in relation to breast cancer occurrence both in premenopausal women (205 case women; 220 control women) and in postmenopausal women (3803 case women; 4071 control women). RESULTS: We found no evidence that having been breast-fed increased breast cancer risk in either premenopausal women (odds ratio [OR] = 0.65; 95% confidence interval [CI] = 0.41-1.04) or postmenopausal women (OR = 0.95; 95% CI = 0.85-1.07). In addition, breast cancer risk was not increased by having been breast-fed by a mother who later developed breast cancer. CONCLUSION: Our results do not support the hypothesis that a transmissible agent in breast milk increases breast cancer risk. Because premenopausal women were not well represented in our study population, our findings with regard to this group may not be generalizable and should be viewed with caution.
Breast Feeding↗
Randomised trial of effects of vitamin supplements on pregnancy outcomes and T cell counts in HIV-1-infected women in Tanzania.
BACKGROUND: In HIV-1-infected women, poor micronutrient status has been associated with faster progression of HIV-1 disease and adverse birth outcomes. We assessed the effects of vitamin A and multivitamins on birth outcomes in such women. METHODS: In Tanzania, 1075 HIV-1-infected pregnant women at between 12 and 27 weeks' gestation received placebo (n=267), vitamin A (n=269), multivitamins excluding vitamin A (n=269), or multivitamins including vitamin A (n=270) in a randomised, double-blind, placebo-controlled trial with a 2x2 factorial design. We measured the effects of multivitamins and vitamin A on birth outcomes and counts of T lymphocyte subsets. We did analyses by intention to treat. RESULTS: 30 fetal deaths occurred among women assigned multivitamins compared with 49 among those not on multivitamins (relative risk 0.61 [95% CI 0.39-0.94] p=0.02). Multivitamin supplementation decreased the risk of low birthweight (<2500 g) by 44% (0.56 [0.38-0.82] p=0.003), severe preterm birth (<34 weeks of gestation) by 39% (0.61 [0.38-0.96] p=0.03), and small size for gestational age at birth by 43% (0.57 [0.39-0.82] p=0.002). Vitamin A supplementation had no significant effect on these variables. Multivitamins, but not vitamin A, resulted in a significant increase in CD4, CD8, and CD3 counts. INTERPRETATION: Multivitamin supplementation is a low-cost way of substantially decreasing adverse pregnancy outcomes and increasing T-cell counts in HIV-1-infected women. The clinical relevance of our findings for vertical transmission and clinical progression of HIV-1 disease is yet to be ascertained.
CD3 Complex↗
A prospective study of association of monounsaturated fat and other types of fat with risk of breast cancer.
BACKGROUND: Animal studies suggest that monounsaturated and polyunsaturated fat may have opposite effects on the risk of breast cancer. METHODS: We performed a population-based prospective cohort study, including 61,471 women aged 40 to 76 years from 2 counties in central Sweden who did not have any previous diagnosis of cancer; 674 cases of invasive breast cancer occurred during an average follow-up of 4.2 years. All subjects answered a validated 67-item food frequency questionnaire at baseline. Cox proportional hazards models were used to obtain adjusted rate ratio (RR) estimates with 95% confidence intervals (CIs). RESULTS: After mutual adjustment of different types of fat, an inverse association with monounsaturated fat and a positive association with polyunsaturated fat were found. The RR for each 10-g increment in daily intake of monounsaturated fat was 0.45 (95% CI, 0.22-0.95), whereas the RR for a 5-g increment of polyunsaturated fat was 1.69 (95% CI, 1.02-2.78); the increments correspond to approximately 2 SDs of intake in the population. Comparing the highest quartile of intake with the lowest, we found an RR of 0.8 (95% CI, 0.5-1.2) for monounsaturated fat and 1.2 (95% CI, 0.9-1.6) for polyunsaturated fat. Saturated fat was not associated with the risk of breast cancer. CONCLUSIONS: Our results indicate that various types of fat may have specific opposite effects on the risk of breast cancer that closely resemble the corresponding effects in experimental animals. Research investigations and health policy considerations should take into account the emerging evidence that monounsaturated fat might be protective for risk of breast cancer.
Adult↗
Body anthropometry and the risk of hip and wrist fractures in men: results from a prospective study.
Available epidemiological information on the associations between body anthropometry and the incidence of fractures in men is limited. We therefore prospectively investigated the association between body anthropometry and the incidence of hip and wrist fractures from low and moderate trauma among 43,053 men who were 40 years to 75 years of age in 1986 when they first enrolled in the Health Professionals Follow-Up Study. After 8 years of follow-up, 201 wrist fracture cases and 56 hip fracture cases were reported. Greater height was associated with significant elevations in both hip and wrist fractures, whereas nonsignificant inverse associations were observed with weight and body mass index. Men in the highest quintile of waist circumference had a relative risk (RR) of 2.57 (95% confidence interval [CI] 0.64 to 10.3) for hip fracture and 2.05 (95% CI 1.06 to 3.96) for wrist fracture when compared with men in the lowest quintile. Waist-to-hip ratio was also positively related to fracture incidence; comparing highest with lowest quintile, the RRs were 3.92 (95% CI 1.07 to 14.3) for hip fracture and 1.50 (95% CI 0.85 to 2.66) for wrist fracture. These anthropometric indicators, in particular waist-to-hip ratio, may be useful for the prediction of hip fracture in adult men.
Adult↗
Predictors of weight change in men: results from the Health Professionals Follow-up Study.
OBJECTIVE: Since the prevalence of adult obesity is increasing in the United States, we examined the effect of changing common habits (exercise, TV viewing, smoking and eating habits) on four year change in body weight. DESIGN: A prospective cohort study of US male health professionals with follow-up from 1988-1992. Participants were 19478 men aged 40-75 in 1986, who were free of cancer, coronary heart disease, stroke and diabetes. METHODS: Multiple regression was used to determine the association between four year change in body weight (from 1988-1992) and common habits, after adjusting for baseline age, hypertension and hypercholesterolemia. RESULTS: For middle aged men, vigorous activity was associated with weight reduction and TV/VCR viewing and eating between meals with weight gain. Quitting smoking and a history of voluntary weight loss prior to the study period were consistently related to weight increase. Recently being on a diet was more strongly associated with weight loss among older men. Over the four year follow-up period, middle-aged men who increased their exercise, decreased TV viewing and stopped eating between meals, lost an average weight of -1.4 kg (95% confidence interval (CI) -1.6 - -1.1 kg), compared to a weight gain of 1.4 kg among the overall population. The prevalence of obesity among middle-aged men was lowest among those who maintained a relatively high level of vigorous physical activity, compared to those who were relatively sedentary. CONCLUSION: These data suggest that improvement in the mix of health habits, particularly increasing vigorous activity, as well as decreasing TV use and changing eating habits, results in weight maintenance or a modest weight loss over four years.
Adult↗
Use of toenail fluoride levels as an indicator for the risk of hip and forearm fractures in women.
The relation between fluoride intake and risk of osteoporotic fractures remains unclear. The lack of individual measures of long-term fluoride intake has limited epidemiologic studies. We used toenail fluoride in this study as a measure of long-term intake to evaluate the relation between fluoride intake and subsequent risk of hip and distal forearm fractures. Between 1982 and 1984, we collected toenail clippings from 62,641 women in the Nurses' Health Study who were free from cancer, heart disease, stroke, and previous hip or forearm fracture. We identified fracture cases (53 proximal femur and 188 distal forearm) through subsequent biennial mailed questionnaires and matched controls to cases on year of birth. The odds ratio of hip fracture among women in the highest quartile of toenail fluoride [ > 5.50 parts per million (ppm)], compared with those in the lowest quartile (> 2.00 ppm), was 0.8 (95% confidence interval = 0.2-4.0), with adjustment for menopausal status, postmenopausal hormone use, caffeine intake, and alcohol consumption. The corresponding adjusted odds ratio for forearm fracture was 1.6 (95% confidence interval = 0.8-3.1). Further adjustment for body mass index, smoking status, and calcium and vitamin D intake did not alter these results.
Adult↗
Menstrual factors in relation to breast cancer risk.
We evaluated menstrual factors in relation to breast cancer risk in a large, population-based, case-control study. Case women were ascertained through state-wide registries covering Wisconsin, Western Massachusetts, Maine, and New Hampshire; control women were randomly selected from driver's license and Medicare lists in each state. Information regarding menstrual characteristics was obtained through a telephone interview. The study population comprised 6888 breast cancer cases and 9529 control women. Because exogenous hormones influence menstrual cycle patterns, we repeated our analyses in a subgroup of women who had never used oral contraceptives or hormone replacement therapy. Our results indicate decreased breast cancer risk with menarcheal age of 15 years or more, relative to menarche at age 13; the relation was stronger among premenopausal [odds ratio (OR), 0.72; 95% confidence interval (CI), 0.57-0.91] as opposed to postmenopausal women (OR, 0.90; 95% CI, 0.80-1.03). Risk was slightly reduced among premenopausal women whose menstrual cycles did not become regular until at least 5 years after onset of menses, relative to those whose cycles became regular within 1 year (OR, 0.80; 95% CI, 0.63-1.02). There was no clear relation between breast cancer risk and irregular menstrual cycles, episodes of amenorrhea, or menstrual cycle length. Early menopause, whether natural or surgical, was associated with decreased breast cancer risk; surgical menopause before age 40 conferred the strongest protective effect (OR, 0.57; 95% CI, 0.47-0.71). We found no evidence of increased risk with late natural menopause (OR, 0.92; 95% CI, 0.80-1.06). Results in the subgroup of women who never used exogenous hormones were similar to those for the entire group.
Adult↗
Non-dietary factors as risk factors for breast cancer, and as effect modifiers of the association of fat intake and risk of breast cancer.
To assess more precisely the relative risks associated with established risk factors for breast cancer, and whether the association between dietary fat and breast cancer risk varies according to levels of these risk factors, we pooled primary data from six prospective studies in North America and Western Europe in which individual estimates of dietary fat intake had been obtained by validated food-frequency questionnaires. Based on information from 322,647 women among whom 4,827 cases occurred during follow-up: the multivariate-adjusted risk of late menarche (age 15 years or more compared with under 12) was 0.72 (95 percent confidence interval [CI] = 0.62-0.82); of being postmenopausal was 0.82 (CI = 0.69-0.97); of high parity (three or more births compared with none) was 0.72 (CI = 0.61-0.86); of late age at first birth (over 30 years of age compared with 20 or under) was 1.46 (CI = 1.22-1.75); of benign breast disease was 1.53 (CI = 1.41-1.65); of maternal history of breast cancer was 1.38 (CI = 1.14-1.67); and history of a sister with breast cancer was 1.47 (CI = 1.27-1.70). Greater duration of schooling (more than high-school graduation compared with less than high-school graduation) was associated significantly with higher risk in age-adjusted analyses, but was attenuated after controlling for other risk factors. Total fat intake (adjusted for energy consumption) was not associated significantly with breast cancer risk in any strata of these non-dietary risk factors. We observed a marginally significant interaction between total fat intake and risk of breast cancer according to history of benign breast disease; with fat intake being associated nonsignificantly positively with risk among women with a previous history of benign breast disease; no other significant interactions were observed. Risks for reproductive factors were similar to those observed in case-control studies; relative risks for family history of breast cancer were lower. We found no clear evidence in any subgroups of a major relation between total energy-adjusted fat intake and breast cancer risk.
Breast Neoplasms↗
Determinants of age at menarche as early life predictors of breast cancer risk.
Age at menarche is one of the few established risk factors for breast cancer; identification of its exogenous determinants could throw light on the origins of breast cancer. We have undertaken an epidemiologic study in Greece to ascertain whether: 1) energy intake, an indicator of physical activity, is associated with later age at menarche; 2) energy-adjusted fat intake is related to earlier age at menarche; and 3) other macronutrients and anthropometric variables are predictors of age at menarche. Anthropometric, socio-economic, familiar, nutritional and lifestyle predictors of age at menarche were studied by interviewing in person 345 female students 9 to 16 years old attending 8 schools of Greater Athens. Menarche was the outcome variable in a proportional hazards model assessing the mutually adjusted incidence rate ratio by a series of predictor variables. In a complementary analysis, age at menarche was the dependent variable among menstruating girls. Consistent results were derived from the main and the complementary analysis. Increased height and body mass index accelerate the occurrence of menarche. Maternal and daughter's ages at menarche are correlated, but there is no evidence of an association with paternal education. Various measures of moderate physical activity as well as increased total energy intake were associated with a delay in age at menarche. Energy-adjusted macronutrients were not associated with age at menarche. It appears that an alteration of energy balance in early life through increased physical activity could delay age at menarche and reduce the risk for breast cancer in later life.
Adolescent↗
Lack of effect of long-term supplementation with beta carotene on the incidence of malignant neoplasms and cardiovascular disease.
BACKGROUND: Observational studies suggest that people who consume more fruits and vegetables containing beta carotene have somewhat lower risks of cancer and cardiovascular disease, and earlier basic research suggested plausible mechanisms. Because large randomized trials of long duration were necessary to test this hypothesis directly, we conducted a trial of beta carotene supplementation. METHODS: In a randomized, double-blind, placebo-controlled trial of beta carotene (50 mg on alternate days), we enrolled 22,071 male physicians, 40 to 84 years of age, in the United States; 11 percent were current smokers and 39 percent were former smokers at the beginning of the study in 1982. By December 31, 1995, the scheduled end of the study, fewer than 1 percent had been lost to follow-up, and compliance was 78 percent in the group that received beta carotene. RESULTS: Among 11,036 physicians randomly assigned to receive beta carotene and 11,035 assigned to receive placebo, there were virtually no early or late differences in the overall incidence of malignant neoplasms or cardiovascular disease, or in overall mortality. In the beta carotene group, 1273 men had any malignant neoplasm (except nonmelanoma skin cancer), as compared with 1293 in the placebo group (relative risk, 0.98; 95 percent confidence interval, 0.91 to 1.06). There were also no significant differences in the number of cases of lung cancer (82 in the beta carotene group vs. 88 in the placebo group); the number of deaths from cancer (386 vs. 380), deaths from any cause (979 vs. 968), or deaths from cardiovascular disease (338 vs. 313); the number of men with myocardial infarction (468 vs. 489); the number with stroke (367 vs. 382); or the number with any one of the previous three end points (967 vs. 972). Among current and former smokers, there were also no significant early or late differences in any of these end points. CONCLUSIONS: In this trial among healthy men, 12 years of supplementation with beta carotene produced neither benefit nor harm in terms of the incidence of malignant neoplasms, cardiovascular disease, or death from all causes.
Adult↗
A prospective study of folate and vitamin B6 and risk of myocardial infarction in US physicians.
OBJECTIVE: To assess prospectively the risk of myocardial infarction (MI) associated with decreased plasma levels of folate and pyridoxal phosphate (PLP, a form of vitamin B6) in relation to elevated levels of total homocysteine (tHcy). DESIGN: Nested case-control study using prospectively collected blood samples. SETTING: Participants in the Physicians' Health Study. SUBJECTS: 14,916 male physicians, aged 40-84 years, with no prior MI or stroke provided plasma samples at baseline and were followed for 7.5 years. Samples from 333 men who subsequently developed MI, and their paired controls matched by age and smoking, were analyzed for folate and PLP levels. MEASURES OF OUTCOME: Acute MI or death due to coronary disease. RESULTS: In a model controlling for diabetes, angina, hypertension, Quetelet's index, and total/high-density lipoprotein cholesterol, men with the lowest 20% of folate levels (< 2.0 ng/mL) had a relative risk of 1.4 (95% confidence interval 0.9-2.3) compared with those in the top 80%. For the lowest 20% of vitamin B6 values, the relative risk was 1.5 (95% CI: 1.0-2.2). When we included both folate and B6 in a model with cardiovascular risk factors, the relative risk of MI for low as compared to high levels of folate was 1.3 (95% CI: 0.8-2.1) and for PLP, 1.3 (95% CI: 0.9-2.1). Adding tHcy to this model did not add significant predictive value (chi sq = 2.0, p > 0.05), except in the first half of the follow-up interval when men with the top 5% of tHcy values had an almost three-fold increase in risk of MI. CONCLUSIONS: Although not statistically significant, these prospective data are compatible with the hypothesis that low dietary intake of folate and/or vitamin B6 contribute to risk of MI.
Adult↗