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Biomedical subjects

W Willett

Publications and source records attributed to W Willett.

At least 37 records · Page 2Linked to original sources
PubMed1996

Evaluation of four methods for determining energy intake in young and older women: comparison with doubly labeled water measurements of total energy expenditure.

The accuracy and precision of four different food intake assessment methods were evaluated in young and older women by comparing reported energy intakes with doubly labeled water measurements total energy expenditure (TEE). A study lasting 8 d was conducted in 10 young women aged 25.2+/-1.1 y (-x+/-SEM) and in 10 older women aged 74.0+/-1.4 y. Free-living TEE was measured over 7 d and food consumption was determined from weighed food intake data (7 d), a 24-h food recall (in duplicate), and two different food-frequency questionnaires [Fred Hutchinson Cancer Research Center (FHCRC)/Block and Willett, both in duplicate]. In addition, body composition was determined by using hydrodensitometry, and strenuous physical activity and the extent of dietary restraint were determined by questionnaire. In young women, 24-h recall gave mean energy intakes that were closest to measures of TEE (-0.34+/-3.71 MJ/d compared with TEE, P=0.178), and energy intakes by food-frequency questionnaires were the only intake data that correlated significantly with individual values for TEE (P<0.05). In older women, food-frequency questionnaires gave mean energy intakes that were closest to measured TEE (+0.53+/-2.95 MJ/d with the Willett questionnaire and -1.19+/-3.02 MJ/d with FHCRC/Block questionnaire). No energy intake data from this group correlated significantly with values for TEE. The 7-d weighed dietary intakes were significantly lower than measured TEE in both young and older women (-2.0 MJ/d in young and older women combined, P<0.001), and did not correlate significantly with values for TEE, although they did most closely mirror the mean difference in TEE between the young and older women (2.30 MJ/d for TEE and 2.11 MJ/d for 7-d weighed intake). These data suggest that none of the methods studied gave accurate estimates of the usual energy requirements of individual subjects. In addition, the results suggest that for some types of studies, simple methods for assessing group mean dietary intake may actually give more accurate information than weighed dietary intakes.

Adult↗
PubMed1994

Association between protein intake and 1-y weight and height gains in Bangladeshi children aged 3-11 y.

We examined 1-y weight and height gains among 238 rural Bangladeshi children aged 3-11 y old to address the hypothesis that dietary protein composition is associated with growth velocity. Energy-adjusted total protein and energy-adjusted protein from sources other than cereal (animal, pulses, and vegetables) were associated with higher weight gains, after adjustment for age, sex, land ownership, diarrhea, acute respiratory infections, other fevers, nutritional status at the beginning of the study, and average body mass index of the mother [daily intake of energy-adjusted noncereal protein (beta +/- SE): 14.2 +/- 6.4 g.y-1.g-1, P = 0.03; total protein: 13.1 +/- 6.3 g.y-1.g-1, P = 0.04; and protein as percent of energy intake: 39.5 +/- 20.2 g.y-1.% of energy from protein-1, P = 0.05]. These findings are compatible with the hypotheses that protein intake may be a limiting factor for weight gain in this population, or that higher protein intake from animal sources (mostly fish) and legumes (lentils and peas) may be accompanied by higher intakes of limiting micronutrients.

Anthropometry↗
PubMed1993

Moderate alcohol intake, increased levels of high-density lipoprotein and its subfractions, and decreased risk of myocardial infarction.

BACKGROUND: Previous studies have suggested that moderate alcohol intake exerts a protective effect against coronary heart disease. Alterations in plasma lipoprotein levels represent one plausible mechanism of this apparent protective effect. METHODS: We therefore examined the interrelation among alcohol consumption, plasma lipoprotein levels, and the risk of myocardial infarction in 340 patients who had had myocardial infarctions and an equal number of age- and sex-matched controls. The case patients were men or women less than 76 years of age with no history of coronary disease who were discharged from one of six hospitals in the Boston area with a diagnosis of a confirmed myocardial infarction. Alcohol consumption was estimated by means of a food-frequency questionnaire. RESULTS: We observed a significant inverse association between alcohol consumption and the risk of myocardial infarction (P for trend, < 0.001 after control for known coronary risk factors). In multivariate analyses, the relative risk for the highest intake category (subjects who consumed three or more drinks per day) as compared with the lowest (those who had less than one drink a month) was 0.45 (95 percent confidence interval, 0.26 to 0.80). The levels of total high-density lipoprotein cholesterol (HDL) and its HDL2 and HDL3 subfractions were strongly associated with alcohol consumption (P for trend, < 0.001 for each). The addition of HDL or either of its subfractions to the multivariate model substantially reduced the inverse association between alcohol intake and myocardial infarction, whereas the addition of the other plasma lipid measurements did not materially alter the relation. CONCLUSIONS: These data confirm the inverse association of moderate alcohol intake with the risk of myocardial infarction and support the view that the effect is mediated, in large part, by increases in both HDL2 and HDL3.

Aged↗
PubMed1993

A randomized trial of vitamin A and vitamin E supplementation for retinitis pigmentosa.

OBJECTIVE: To determine whether supplements of vitamin A or vitamin E alone or in combination affect the course of retinitis pigmentosa. DESIGN: Randomized, controlled, double-masked trial with 2 x 2 factorial design and duration of 4 to 6 years. Electroretinograms, visual field area, and visual acuity were measured annually. SETTING: Clinical research facility. PATIENTS: 601 patients aged 18 through 49 years with retinitis pigmentosa meeting preset eligibility criteria. Ninety-five percent of the patients completed the study. There were no adverse reactions. INTERVENTION: Patients were assigned to one of four treatment groups receiving 15,000 IU/d of vitamin A, 15,000 IU/d of vitamin A plus 400 IU/d of vitamin E, trace amounts of both vitamins, or 400 IU/d of vitamin E. MAIN OUTCOME MEASURE: Cone electroretinogram amplitude. RESULTS: The two groups receiving 15,000 IU/d of vitamin A had on average a slower rate of decline of retinal function than the two groups not receiving this dosage (P = .01). Among 354 patients with higher initial amplitudes, the two groups receiving 15,000 IU/d of vitamin A were 32% less likely to have a decline in amplitude of 50% or more from baseline in a given year than those not receiving this dosage (P = .01), while the two groups receiving 400 IU/d of vitamin E were 42% more likely to have a decline in amplitude of 50% or more from baseline than those not receiving this dosage (P = .03). While not statistically significant, similar trends were observed for rates of decline of visual field area. Visual acuity declined about 1 letter per year in all groups. CONCLUSIONS: These results support a beneficial effect of 15,000 IU/d of vitamin A and suggest an adverse effect of 400 IU/d of vitamin E on the course of retinitis pigmentosa.

Adolescent↗
PubMed1993

Obesity. Workshop III. AHA Prevention Conference III. Behavior change and compliance: keys to improving cardiovascular health.

The workshop provided the opportunity to discuss issues and develop and integrate ideas. The following recommendations for public policies, education programs, and high-priority research initiatives were developed: Recommendations for Public Policies: Focus on prevention by requiring school programs to emphasize appropriate diet, physical activity, and general health guidance to promote cardiovascular health and prevent disease through federal funding. Provide better access to exercise (city planning, work-site interventions). Influence food availability and accessibility. Influence reimbursement policies for effective early intervention and prevention strategies for obesity. Reevaluate policies for use of drugs in the treatment of obesity. Recommendations for Education Programs: Sponsor scientific workshop to: Define the most appropriate weight standards for prevention and treatment. Identify who should lose weight and why, when, and how. Promote the fact that obesity is an important health risk factor, even at moderate levels, and that excess visceral fat is particularly hazardous. Target health care professionals, consumers, and the media for education about: Nature of obesity as a heterogeneous syndrome. Recommendations for diet, exercise, behavioral interventions, drugs, and surgery. Recognition of special needs of populations of different ethnicity, gender, age, etc. State-of-the-art treatment and treatment programs. High-Priority Research Initiatives: Build better bridges between basic research and treatment/prevention practices. Acknowledge that obesity is a heterogeneous syndrome that may best be characterized as different obesities. Research on defining subtypes. Implications for etiology and treatment. Better characterization of genotypes and phenotypes. Study the effects of weight loss, weight gain,and weight cycling on medical and psychosocial outcomes and mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Diet and coronary heart disease: a case-control study in Athens, Greece.

We conducted a case-control study in Athens, Greece, between January 1990 and April 1991 to examine the association between diet and coronary heart disease. The case series comprised 329 patients with electrocardiographically confirmed first coronary infarct or a first positive coronary arteriogram, or both, who were admitted to a major teaching hospital during a 16-month period. Controls were 570 patients admitted to the same hospital for minor conditions believed to be unrelated to nutrition. Total energy intake was inversely associated with coronary heart disease risk, a quintile energy increase corresponding to a relative risk of 0.96. After controlling for total energy intake, dietary fat was positively related to coronary heart disease, and total carbohydrates were negatively related to coronary heart disease, the nutrient-specific relative risks for a quintile increase being 1.19 (95% confidence interval = 0.96-1.48) and 0.81 (95% confidence interval = 0.67-0.97), respectively. Major fat components (saturated, monounsaturated, and polyunsaturated fat) did not appear to have differential risk implications for coronary heart disease; however, cooking with margarine was associated with an increased relative risk (1.87; 95% confidence interval = 0.82-4.28). Dietary proteins, cholesterol, and vitamin C were not associated with coronary heart disease.

Aged↗
PubMed1992

Maternal heat exposure and neural tube defects.

OBJECTIVE: To determine if exposure to hot tub, sauna, fever, or electric blanket during early pregnancy was associated with an increased risk for neural tube defects (NTDs). DESIGN: Prospective follow-up study. SETTING: Mostly private obstetric practices, primarily in New England. PARTICIPANTS: A cohort of 23,491 women having serum alpha-fetoprotein screening or an amniocentesis were identified. Complete exposure and outcome information was available for 97% of these women. OUTCOME MEASURES: Relative risks (RRs) were used to compare incidence of NTD in those exposed to heat with those who were not exposed to any heat. Crude RRs were calculated directly from the data. Unconfounded RRs were calculated using logistic regression. RESULTS: Women reporting any heat exposure (sauna, hot tub, fever, or electric blanket) in early pregnancy had a crude risk of their fetuses developing NTD of 1.6 (95% CI [confidence interval], 0.9 to 2.9). Women reporting exposure to sauna, hot tub, or fever in early pregnancy had a crude risk of their fetuses developing NTD 2.2 times that of women without heat exposure (95% CI, 1.2 to 4.1). For hot tub use, the crude RR was 2.9 (95% CI, 1.4 to 6.3); for sauna, 2.6 (95% CI, 0.7 to 10.1); for fever, 1.9 (95% CI, 0.8 to 4.1); and for electric blanket, 1.2 (95% CI, 0.5 to 2.6). Multivariate adjusted RRs for individual heat sources, after controlling for maternal age, folic acid supplements, family history of NTD, and exposure to other heat sources, were for hot tub use, 2.8 (95% CI, 1.2 to 6.5); sauna, 1.8 (95% CI, 0.4 to 7.9); fever, 1.8 (95% CI, 0.8 to 4.1); and electric blanket, 1.2 (95% CI, 0.5 to 2.6). When only hot tub, sauna, and fever were considered and the women's exposure to each tallied, compared with no heat exposure, the RR for NTDs increased from 1.9 (95% CI, 0.9 to 3.7) after one type of heat exposure to 6.2 (95% CI, 2.2 to 17.2) after two types of heat exposure. CONCLUSIONS: Exposure to heat in the form of hot tub, sauna, or fever in the first trimester of pregnancy was associated with an increased risk for NTDs. Hot tub exposure appeared to have the strongest effect of any single heat exposure. Exposure to electric blanket was not materially associated with increased risk for NTDs.

Cohort Studies↗
PubMed1992

Breast cancer (3).

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Antineoplastic Agents↗
PubMed1992

Breast cancer (1)

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Breast Neoplasms↗
PubMed1992

Maternal zinc and fetal neural tube defects.

Among the factors implicated in the heterogeneous etiology of neural tube defects (NTDs) is the trace element zinc (Zn). In a case-control study, we collected midtrimester maternal toenail samples for multiple trace element analyses, including Zn, which were assayed by neutron activation analysis. We studied 17 women with NTD offspring and 1,787 controls. The crude OR for NTD comparing Zn values greater than normal range to normal Zn values was 3.2 (95% CI 1.1,9.7). These results were not materially affected when adjustment was made for folic acid supplementation. An overall increased risk for NTD associated with increasing toenail Zn was also evident. A matched subset of 17 cases and 73 controls yielded a crude OR of 3.1 (95% CI 0.9,10.3) when cases with elevated Zn (greater than or equal to 120 ppm) were compared to those with normal Zn. Matched analyses controlling for folic acid supplements, family history of NTD, assay batch, age of mother and year of delivery yielded an OR of 5.0 (95% CI 1.1,21.6). This study reveals an association between increased toenail Zn in the second trimester of pregnancy and the risk of having a child with an NTD. Whether Zn sequestration has resulted in relative Zn deficiency at the site of neural tube closure remains uncertain.

Case-Control Studies↗
PubMed1991

Alcohol and other dietary factors in relation to serum hormone concentrations in women at climacteric.

The relationships between concentrations of endogenous hormones in serum and dietary intakes of alcohol, fats, fiber, and caffeine were examined in 325 healthy Massachusetts women aged 50-60 y who reported having a normal menstrual period within the previous 12 mo. Diet was assessed by a semiquantitative food frequency questionnaire. Hormones assayed were estrone, estradiol, percent free estradiol, sex-hormone-binding globulin (SHBG), cortisol, and gonadotropins. Alcohol intake was not associated with concentrations of estrogens or gonadotropins. Neither total fat intake nor the fat composition of the diet influenced hormone concentrations. Fiber intake was positively correlated with SHBG; no associations with estrogens were seen. Caffeine intake was inversely correlated with free estradiol and positively correlated with SHBG. These data suggest that fat, fiber, and alcohol intakes of US women at climacteric are not determinants of variations in estrone and either total or percent free estradiol.

Alcohol Drinking↗
PubMed1991

A prospective cohort study of nutrient intake and age at menarche.

A cohort of 213 girls (aged 10 y, range +/- 9 mo) whose parents reported their dietary intakes (including nutritional supplements) using a semiquantitative food frequency questionnaire, was followed for 4 y until 82% of the 194 parents who responded to follow-up letters had reported that their daughters had had their first menstrual periods. The relative risk (RR) of menarche before age 12.5 y was 2.0 [95% confidence interval (CI) = 1.1-3.8] for the tallest girls (greater than 150 cm) compared with the shortest girls (less than 130 cm). The RR was 2.1 (95% CI = 1.1-3.8) for the fattest girls [Quetelet's index of relative weight (in kg/m2) greater than 19] vs the leanest girls (less than 15). After adjusting for height and Quetelet's index, menarcheal age was not associated with intake of energy nor energy-adjusted intake of protein, fat, or carbohydrate. The overall results are consistent with the hypothesis that nutritional factors influence age at menarche mainly through their effects on accumulation of adipose tissue.

Age Factors↗