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W Willett

Publications and source records attributed to W Willett.

At least 55 records · Page 3Linked to original sources
PubMed1991

Diet and peripheral arterial occlusive disease: the role of poly-, mono-, and saturated fatty acids.

A case-control study concerning the association between diet and peripheral arterial occlusive disease was conducted in Athens, Greece. The case series consisted of 100 patients with this disease, whereas controls were 100 patients with conditions requiring minor surgical care who were admitted to the same teaching hospital. Diet was ascertained through a semiquantitative food frequency questionnaire. Nutrient intakes for individuals were estimated by multiplying the nutrient content of a selected typical portion size for each specified food item by the frequency that the food was used per month and summing these estimates for all food items. Data were analyzed using multiple logistic regression procedures, controlling for total energy intake by taking nutrient residuals and by using multivariate nutrient density models. Saturated fatty acids (odds ratio (OR) and 95% confidence interval (CI) contrasting the 75th centile (upper) with the 25th centile = 1.96 and 1.14-3.39), proteins (OR = 2.86, 95% CI 1.47-5.55), and dietary cholesterol (OR = 6.07, 95% CI 2.74-13.46) were associated with increased risk of peripheral arterial occlusive disease, whereas polyunsaturated fatty acids (OR = 0.48, 95% CI 0.24-0.93) and crude fiber (OR = 0.33, 95% CI 0.17-0.64) were related to reduced risk. Monounsaturated fatty acids and, by inference, olive oil occupy an intermediate neutral position between polyunsaturates and saturates (corresponding OR = 1.14, 95% CI 0.68-1.91). Higher intakes of fiber and vitamin C were associated with lower risk of peripheral arterial occlusive disease. The low occurrence of atherosclerotic diseases in Greece and other Mediterranean countries may be due to the substitution of olive oil in place of saturated fats and/or the consumption of a diet high in vegetables, fruits, and other fiber-containing foods.

Arterial Occlusive Diseases↗
PubMed1990

Coffee, caffeine, and cardiovascular disease in men.

BACKGROUND: For many years, an association between coffee consumption and the risk of coronary heart disease has been suspected. Although based on small numbers of end points, a prospective study has suggested a particularly strong association between recent coffee drinking and the incidence of cardiovascular disease. METHODS: We examined prospectively the relation of coffee consumption with the risk of myocardial infarction, need for coronary-artery bypass grafting or angioplasty, and risk of stroke in a cohort of 45,589 U.S. men who were 40 to 75 years old in 1986 and who had no history of cardiovascular disease. RESULTS: During two years of follow-up observation, 221 participants had a nonfatal myocardial infarction or died of coronary heart disease, 136 underwent coronary-artery surgery or angioplasty, and 54 had a stroke. Total coffee consumption was not associated with an increased risk of coronary heart disease or stroke. The age-adjusted relative risk for all cardiovascular disease among participants who drank four or more cups of coffee per day was 1.04 (95 percent confidence intervals, 0.74 to 1.46). Increasing levels of consumption of caffeinated coffee were not associated with higher risks of cardiovascular disease. Higher consumption of decaffeinated coffee, however, was associated with a marginally significant increase in the risk of coronary heart disease (relative risk, 1.63; 95 percent confidence interval, 1.02 to 2.60). Finally, we observed no pattern of increased risk across the subgroups of participants with increasing intakes of caffeine from all sources. Adjustment for major cardiovascular-risk indicators, dietary intake of fats, and cholesterol intake did not materially alter these associations. CONCLUSIONS: These findings do not support the hypothesis that coffee or caffeine consumption increases the risk of coronary heart disease or stroke.

Adult↗
PubMed1990

A case-control study of diet and risk of renal adenocarcinoma.

We examined dietary and other risk factors for renal adenocarcinoma in a case-control study of 203 incident and 207 prevalent cases and 605 neighborhood controls. Using unconditional logistic regression to control selection biases identified in an adjunct study, we found exposure odds ratios (OR) similar to those from other studies: 1.9 (with a 95% confidence interval (Cl) from 0.8 to 4.4) for smoking 2 packs of cigarettes per day; 3.8 (95% Cl: 0.78-18) for 3 or more packs per day; 1.7 (95% Cl: 0.9-3.2) for women and 1.7 (95% Cl: 1.1-2.8) for men in the highest quintile of relative weight (kg/m2); 2.0 (95% Cl: 1.3-3.1) for northeastern European ancestry; and 2.3 (95% Cl: 1.3-4.1) for history of kidney stones. Incident cases consumed more meats and fewer vegetables than controls: the age-sex-education-adjusted OR for average intake of 85 g (3 oz) of beef per day was 3.4 (95% Cl: 1.6-7.2). Inverse associations were seen for most vegetables. Dietary animal protein, animal fat, and saturated fat, with and without energy adjustment, were weakly associated with disease in unconditional and conditional logistic regressions. Prior hypotheses concerning intake of cholesterol, beta-carotene, preformed vitamin A, and cruciferous vegetables were not corroborated.

Adenocarcinoma↗
PubMed1989

Multivitamin/folic acid supplementation in early pregnancy reduces the prevalence of neural tube defects.

We examined the relation of multivitamin intake in general, and folic acid in particular, to the risk of neural tube defects in a cohort of 23,491 women undergoing maternal serum alpha-fetoprotein screening or amniocentesis around 16 weeks of gestation. Complete questionnaires and subsequent pregnancy outcome information was obtained in 22,776 pregnancies, 49 of which ended in a neural tube defect. The prevalence of neural tube defect was 3.5 per 1000 among women who never used multivitamins before or after conception or who used multivitamins before conception only. The prevalence of neural tube defects for women who used folic acid-containing multivitamins during the first 6 weeks of pregnancy was substantially lower--0.9 per 1000 (prevalence ratio, 0.27; 95% confidence interval, 0.12 to 0.59 compared with never users). For women who used multivitamins without folic acid during the first 6 weeks of pregnancy and women who used multivitamins containing folic acid beginning after 7 or more weeks of pregnancy, the prevalences were similar to that of the nonusers and the prevalence ratios were close to 1.0.

Adult↗
PubMed1989

The search for the causes of breast and colon cancer.

Epidemiological studies of breast and colon cancers implicate diet as a causative factor but the evidence is stronger for colon cancer, the occurrence of which may be reduced by diets with less animal fat and more fruit and vegetables.

Alcohol Drinking↗
PubMed1989

An overview of issues related to the correction of non-differential exposure measurement error in epidemiologic studies.

Procedures to correct estimates of association in epidemiologic studies for the effects of exposure measurement error have rarely been employed in practice. The application of correction procedures would be enhanced by methods that allow the inclusion of covariates, provide corrected confidence intervals, are compatible with commonly employed analytic methods, and that are clearly communicated to potential users. Before using such a procedure, it is important to clearly specify the conceptual 'true' exposure, determine the nature of the measurement error, and decide whether a reproducibility study or validity study is required to quantify the error. The careful use of correction procedures promises to improve our knowledge of the quantitative relationships between many exposures and disease since it is likely that we have substantially underestimated the effects of many exposures and overstated our confidence in null results.

Biometry↗
PubMed1989

Predictive values, relative risks, and overall benefits of high and low maternal serum alpha-fetoprotein screening in singleton pregnancies: new epidemiologic data.

In a prospective study of maternal serum alpha-fetoprotein screening for both high and low values, we assessed the overall predictive value, sensitivity, specificity and relative risks for congenital defects and complications of pregnancy. Among 13,486 women with singleton pregnancies interviewed at the time of screening (15 to 20 weeks of gestation), 3.9% had high and 3.4% had low values. A high maternal serum alpha-fetoprotein value was associated with the following adverse outcomes: neural tube defects (relative risk = 224), other major congenital defects (relative risk = 4.7), fetal deaths (relative risk = 8.1), neonatal death (relative risk = 4.7), low birth weight (relative risk = 4.0), newborn complications (relative risk = 3.6), oligohydramnios (relative risk = 3.4), abruptio placentae (relative risk = 3.0) and preeclamptic toxemia (relative risk = 2.3). A low maternal serum alpha-fetoprotein value was associated with chromosomal defects (relative risk = 11.6) for fetal death (relative risk = 3.3). Either high or low maternal serum alpha-fetoprotein values were associated with 34.2% of all major congenital defects, 19.1% of all stillbirths and fetal-neonatal deaths, 11.0% of major pregnancy complications, and 15.9% of serious newborn complications. Maternal serum alpha-fetoprotein screening provides an important adjunctive tool for the identification of high-risk pregnancy and adverse neonatal outcome.

Adolescent↗
PubMed1989

Diet and the risk of breast cancer.

This article presents a review of the epidemiologic evidence on the relationship between breast cancer risk and nutritional factors. Particular attention is given to the relationship between breast cancer and dietary fats. Other factors discussed include intake of alcohol, micronutrients, and caffeine.

Animals↗
PubMed1988

Risk of breast cancer among Greek women in relation to nutrient intake.

A case-control study of the role of diet in the cause of breast cancer was conducted in Athens, Greece. The case series consisted of 120 consecutive patients with histologically confirmed breast cancer admitted to either of two teaching hospitals over a 12-month period. The controls were 120 patients admitted to a teaching hospital for trauma and orthopedic conditions during the same period. Dietary histories concerning the frequency of consumption of 120 foods and drinks were obtained by interview. Nutrient intakes for individuals were estimated by multiplying the nutrient content of a selected typical portion size for each specified food item by the frequency that the food was used per month and summing these estimates for all food items. Cases reported significantly less frequent consumption of vitamin A after controlling for total caloric intake, potential external confounding variables and other nutrients associated with breast cancer risk. The odds ratio estimated for consumption of vitamin A equal to the value of the 90th centile versus consumption equal to the value of the 10th centile was 0.46 with 90% confidence limits 0.26-0.82. There was no evidence that high intake of dietary fat increases the risk of breast cancer.

Breast Neoplasms↗
PubMed1988

Malnutrition and diarrhea. A longitudinal study among urban Mexican children.

To address the hypothesis that malnutrition is associated with an increased risk of diarrhea, the authors identified a cohort of 284 Mexican children less than two years of age in order to equally represent different degrees of nutritional status. Nutritional status, defined anthropometrically, was measured at baseline and every three months for a total follow-up period of one year. The occurrence of diarrhea was assessed by weekly home visits. Among the combinations of weight and length examined, weight for age was the strongest predictor of subsequent diarrhea during a three-month interval. Among normally nourished children, the incidence of diarrhea was 3.3 episodes per year; among those mildly malnourished, 3.7 episodes per year (relative risk (RR) = 1.1); and among the moderately malnourished, 6.0 episodes per year (RR = 1.8). Adjustment for demographic, seasonal, and socioeconomic variables only slightly reduced this association. Nutritional status was most strongly related to the occurrence of two or more episodes during a three-month follow-up interval, and this effect was most clearly seen among children with diarrhea in the preceding interval. In a multiple logistic analysis that included potentially confounding variables as well as an autoregressive term to account for the nonindependence of repeated observations, the relative risk of two or more episodes of diarrhea during an interval was 1.8 (95% confidence interval 1.1-2.9) for moderately malnourished children compared with those who were normally nourished or mildly malnourished. These data lend support to the hypothesis that malnutrition predisposes to the occurrence of diarrhea among young children.

Diarrhea, Infantile↗
PubMed1987

Nutritional epidemiology: issues and challenges.

Studies of diet in relation to disease raise methodological challenges considerably more complicated than in most epidemiological investigations. Diet is not a single exposure, but rather a complex set of many intercorrelated continuous variables. Moreover, these variables are likely to have non-linear relationships with disease and interact with each other. Many epidemiologists have questioned whether useful measurements of individual diets could be made within populations, due to homogeneity of food intake and imprecision of assessment methods. However, in several recent studies it has been possible to demonstrate reasonable levels of correlation between simple, structured food frequency questionnaires and detailed, weighed assessments of diet. This provides evidence documenting that between-person variation in diet does exist and that simple questionnaires are sufficiently accurate to measure these differences. For a limited set of nutrients, biochemical measurements provide an alternative assessment of exposure. It remains to be seen whether these methodologies can be reliably employed in case-control studies since even small biases due to the presence of illness, which may affect recall of diet or the levels of biochemical parameters, will seriously distort relationships between diet and disease.

Diet↗
PubMed1987

A prospective cohort study of postmenopausal hormone use and risk of breast cancer in US women.

The association between history of postmenopausal hormone use as of 1976 and breast cancer incidence during 1976-1980 was examined prospectively among 33,335 married, postmenopausal registered nurses aged 30-55 years at entry. Half the women reported postmenopausal hormone use, and one fourth had taken these drugs for over five years. During 1976-1980, 221 new cases of breast cancer were identified. The relative risk (RR) for those who had used postmenopausal hormones when compared with women who had never used them was 1.1 (95% confidence limits (CL) 0.8, 1.4); for current and past users, the relative risks were 1.0 (95% CL 0.7, 1.4) and 1.3 (95% CL 0.9, 1.8), respectively. These ratios were not substantially modified by whether or not a woman's ovaries had been removed or by other known breast cancer risk factors. No increase in breast cancer risk was apparent among women who had used postmenopausal hormones for less than five years (RR = 1.0, 95% CL 0.5, 1.6). An apparent effect among the subgroup of women who had used them for five to nine years (RR = 1.5, 95% CL 1.0, 2.2) was not present among the few women with longer-term use (RR = 0.9, 95% CL 0.4, 1.6). These findings are moderately reassuring, but since there are as yet few women in this cohort with long-term durations of use and, particularly, with long intervals since first use, continued follow-up of this and other cohorts will be required before firm conclusions can be drawn, especially among specific subgroups.

Adult↗
PubMed1986

Vitamin A, carotenoids, and retinoids.

One promising area of current research in chemoprevention is the possibility that micronutrients, including vitamin A analogues, may decrease cancer incidence. The term "vitamin A" refers either to retinol (preformed vitamin A) and its synthetic analogues, or to certain carotenoids (provitamin A), which are converted to retinol in the body, as needed. Retinol and the other retinoids are integrally involved in cell growth and differentiation, which may affect carcinogenesis. Such a role has been supported by a large number of in vitro and animal experiments. Data from studies among humans are sparse, in part because most dietary studies have been conducted in populations in which the vast majority of vitamin A intake is actually beta-carotene and other carotenoids, found in carrots and other vegetables and fruits. Although the carotenoids do not have the hormone-like properties of retinol, they do have a potent antioxidant effect and could thus reduce cancer risk by preventing tissue damage due to oxidation. This possibility is supported by data from a large number of observational epidemiologic studies, most of which have consistently found an inverse relation between consumption of carotene-rich vegetables and cancer risk. However, the only direct way to determine whether carotenoids have a beneficial effect is through large, carefully conducted randomized trials. Several such studies are currently underway and should provide sound evidence on which future medical policy and practice can be based.

Carotenoids↗
PubMed1986

Oral contraceptives and breast cancer. A prospective cohort study.

In 1976, information on oral contraceptive (OC) use as well as numerous risk factors for breast cancer was provided by 121,964 married female registered nurses aged 30 to 55 years. Ninety-two percent of women in the cohort completed follow-up questionnaires, and vital records were systematically searched to ascertain deaths among nonrespondents. After four years of follow-up, 592 incident cases of breast cancer were identified. Compared with never users, the age-adjusted relative risk (RR) of breast cancer, regardless of menopausal status, among all women who had ever used OCs was 1.0. Among premenopausal women compared with those who had never used OCs, the RR of breast cancer was 1.5 for current use of OCs in 1976 and 1.0 for past use. Among postmenopausal women, the RR for past use of OCs was 1.0. These estimates were essentially unaltered after controlling for other known risk factors for breast cancer in multiple logistic regression analysis. Furthermore, there was no modification of these effects by family history of breast cancer, age at first use, timing of the first birth, or other breast cancer risk factors. Data on past use of OCs provide substantial reassuring evidence that there is no large excess risk of breast cancer within a few years of cessation of pill use. The observed moderate elevation of breast cancer risk with current use was of borderline statistical significance. However, the observation was based on 29 cases and may reflect the effect of sampling variability, as most other studies have not observed a relationship between current use of OCs and breast cancer in women of this age.

Adult↗