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Biomedical subjects

D J Hunter

Publications and source records attributed to D J Hunter.

At least 91 records · Page 5Linked to original sources
PubMed1999

Dietary fat and protein in relation to risk of non-Hodgkin's lymphoma among women.

BACKGROUND: Non-Hodgkin's lymphoma occurs more frequently in individuals with suppressed immune status, and some types of dietary fat and protein have been associated with decreased immune responses. In this study, we examined the intake of specific types of dietary fat and protein in relation to the risk of non-Hodgkin's lymphoma. METHODS: We documented 199 incident cases of non-Hodgkin's lymphoma in a cohort of 88 410 women, who were enrolled in the Nurses' Health Study and were aged 34-60 years in 1980, during 14 years of follow-up. Relative risks of the disease and 95% confidence intervals (95% CIs) were calculated. All P values are two-sided and were considered to be statistically significant for P<.05. RESULTS: Intake of saturated fat was associated with an increase in risk that was not statistically significant; the multivariate relative risk for the highest versus the lowest quintiles of intake was 1.4 (95% CI = 0.7-3.0; P for trend =.42). Intake of beef, pork, or lamb as a main dish was associated with a statistically significantly increased risk of non-Hodgkin's lymphoma; the multivariate relative risk for consumption of these meats at least once per day as compared with less than once per week was 2.2 (95% CI = 1.1-4.4; P for trend =.002). Higher intake of trans unsaturated fat was also statistically significantly associated with an increased risk of the disease; the multivariate relative risk for the highest versus the lowest quintiles was 2.4 (95% CI = 1.3-4.6; P for trend =.01). Higher intake of red meat cooked by broiling or barbecuing-but not by roasting, pan-frying, or boiling or stewing-was associated with an increase in risk that was not statistically significant. CONCLUSIONS: Greater dietary intake of certain meats and fats was associated with a higher risk of non-Hodgkin's lymphoma. These relationships and their potential mechanisms deserve further examination.

Adult↗
PubMed1999

Weight cycling, weight gain, and risk of hypertension in women.

To assess prospectively the relation between body mass index, weight gain, repeated intentional weight losses, and the risk of self-reported hypertension, the authors studied 46,224 women who were participants in the Nurses Health Study II, who were free of hypertension in 1993, and who completed questions on intentional weight losses between 1989 and 1993. Women who reported they had intentionally lost > or =20 lbs (9 kg) > or =3 times were classified as severe weight cyclers. Women who had intentionally lost > or =10 lbs (4.5 kg) > or =3 times, but who did not meet the criteria for severe weight cycling, were classified as mild weight cyclers. Between 1993 and 1995, 1,107 incident cases of diagnosed hypertension were reported. Body mass index and weight gain, but not weight cycler status, were independently associated with the development of hypertension. For each 10 lb (4.5 kg) gain in weight between 1989 and 1993, the risk of hypertension increased 20% (odds ratio (OR) = 1.20, 95% confidence interval (CI) 1.15, 1.24). After adjustment for body mass index and weight gain, the risks associated with mild weight cycling (OR = 1.15, 95% CI 1.00, 1.33) and severe weight cycling (OR = 1.13, 95% CI 0.79, 1.61) were small and not significant. Thus, the results of this study offer support for the current weight guidelines and provide further evidence of the health risks associated with excessive weight and weight gain. However, these data do not suggest an independent effect of weight cycling on risk of hypertension.

Adult↗
PubMed1999

Dietary factors and the survival of women with breast carcinoma.

BACKGROUND: Little is known regarding how specific dietary factors affect the survival of women with breast carcinoma. METHODS: Female registered nurses were followed with biennial questionnaires in a prospective cohort with 18 years of follow-up. Participants were women with breast carcinoma (n = 1982) diagnosed between 1976-1990 who completed a food frequency questionnaire after diagnosis. The main outcome measure was time to death from any cause. Analysis was made by multivariate Cox proportional hazards models. RESULTS: In multivariate analyses of diet after diagnosis, no apparent association was found between fat intake and mortality. The relative risk (and 95% confidence interval) of mortality comparing the highest with the lowest quintile of protein intake was 0.65 (0.47-0.88). There was no association between red meat and mortality. These associations were similar in analyses with breast carcinoma death as the outcome. CONCLUSIONS: No survival advantage was found for a low fat diet after a diagnosis of breast carcinoma. However, increased survival was observed among women eating more protein, but not red meat. The findings suggest that differences in diet may affect survival after a diagnosis of breast carcinoma and should be examined in greater detail.

Breast Neoplasms↗
PubMed1999

A prospective study of folate intake and the risk of breast cancer.

CONTEXT: Folate is involved in DNA synthesis and methylation and may reduce breast cancer risk, particularly among women with greater alcohol consumption. OBJECTIVES: To assess the association between folate intake and risk of breast cancer and whether higher folate intake may reduce excess risk among women who consume alcohol. DESIGN: Prospective cohort study performed in 1980, with 16 years of follow-up. SETTING AND PARTICIPANTS: A total of 88818 women who completed the dietary questionnaire section of the Nurses' Health Study in 1980. MAIN OUTCOME MEASURE: Incidence of invasive breast cancer by levels of folate and alcohol intake. RESULTS: A total of 3483 cases of breast cancer were documented. Total folate intake was not associated with overall risk of breast cancer. However, among women who consumed at least 15 g/d of alcohol, the risk of breast cancer was highest among those with low folate intake. For total folate intake of at least 600 microg/d compared with 150 to 299 microg/d, the multivariate relative risk (RR) was 0.55 (95% confidence interval [CI], 0.39-0.76; P for trend = .001). This association was only slightly attenuated after additional adjustment for intake of beta carotene, lutein/zeaxanthin, preformed vitamin A, and total vitamins C and E. The risk of breast cancer associated with alcohol intake was strongest among women with total folate intake of less than 300 microg/d (for alcohol intake > or =15 g/d vs <15 g/d, multivariate RR, 1.32; 95% CI, 1.15-1.50). For women who consumed at least 300 microg/d of total folate, the multivariate RR for intake of at least 15 g/d of alcohol vs less than 15 g/d was 1.05 (95% CI, 0.92-1.20). Current use of multivitamin supplements, the major source of folate, was associated with lower breast cancer risk among women who consumed at least 15 g/d of alcohol (for current users of supplements vs never users, RR, 0.74; 95% CI, 0.59-0.93). CONCLUSIONS: Our findings suggest that the excess risk of breast cancer associated with alcohol consumption may be reduced by adequate folate intake.

Adult↗
PubMed1999

Dietary carotenoids and vitamins A, C, and E and risk of breast cancer.

BACKGROUND: Data on intake of specific carotenoids and breast cancer risk are limited. Furthermore, studies of vitamins A, C, and E in relation to breast cancer risk are inconclusive. We have conducted a large, prospective study to evaluate long-term intakes of these nutrients and breast cancer risk. METHODS: We examined, by use of multivariate analysis, associations between intakes of specific carotenoids, vitamins A, C, and E , consumption of fruits and vegetables, and breast cancer risk in a cohort of 83234 women (aged 33-60 years in 1980) who were participating in the Nurses' Health Study. Through 1994, we identified 2697 incident cases of invasive breast cancer (784 premenopausal and 1913 postmenopausal). RESULTS: Intakes of beta-carotene from food and supplements, lutein/zeaxanthin, and vitamin A from foods were weakly inversely associated with breast cancer risk in premenopausal women. Strong inverse associations were found for increasing quintiles of alpha-carotene, beta-carotene, lutein/zeaxanthin, total vitamin C from foods, and total vitamin A among premenopausal women with a positive family history of breast cancer. An inverse association was also found for increasing quintiles of beta-carotene among premenopausal women who consumed 15 g or more of alcohol per day. Premenopausal women who consumed five or more servings per day of fruits and vegetables had modestly lower risk of breast cancer than those who had less than two servings per day (relative risk [RR] = 0.77; 95% confidence interval [CI] = 0.58-1.02); this association was stronger among premenopausal women who had a positive family history of breast cancer (RR = 0.29; 95% CI = 0.13-0.62) or those who consumed 15 g or more of alcohol per day (RR = 0.53; 95% CI = 0.27-1.04). CONCLUSIONS: Consumption of fruits and vegetables high in specific carotenoids and vitamins may reduce premenopausal breast cancer risk.

Adult↗
PubMed1999

Association of dietary intake of fat and fatty acids with risk of breast cancer.

CONTEXT: High intakes of fat and specific fatty acids, including total, animal, saturated, polyunsaturated, and trans-unsaturated fats, have been postulated to increase breast cancer risk. OBJECTIVE: To determine whether intakes of fat and fatty acids are associated with breast cancer. DESIGN AND SETTING: Cohort study (Nurses' Health Study) conducted in the United States beginning in 1976. PARTICIPANTS: A total of 88795 women free of cancer in 1980 and followed up for 14 years. MAIN OUTCOME MEASURE: Relative risk (RR) of invasive breast cancer for an incremental increase of fat intake, ascertained by food frequency questionnaire in 1980, 1984, 1986, and 1990. RESULTS: A total of 2956 women were diagnosed as having breast cancer. Compared with women obtaining 30.1% to 35% of energy from fat, women consuming 20% or less had a multivariate RR of breast cancer of 1.15 (95% confidence interval [CI], 0.73-1.80). In multivariate models, the RR (95% CI) for a 5%-of-energy increase was 0.97 (0.94-1.00) for total fat, 0.98 (0.96-1.01) for animal fat, 0.97 (0.93-1.02) for vegetable fat, 0.94 (0.88-1.01) for saturated fat, 0.91 (0.79-1.04) for polyunsaturated fat, and 0.94 (0.88-1.00) for monounsaturated fat. For a 1% increase in energy from trans-unsaturated fat, the values were 0.92 (0.86-0.98), and for a 0.1% increase in energy from omega-3 fat from fish, the values were 1.09 (1.03-1.16). In a model including fat, protein, and energy, the RR for a 5% increase in total fat, which can be interpreted as the risk of substituting this amount of fat for an equal amount of energy from carbohydrate, was 0.96 (95% CI, 0.93-0.99). In similar models, no significant association of risk was evident with any major types of fat. CONCLUSION: We found no evidence that lower intake of total fat or specific major types of fat was associated with a decreased risk of breast cancer.

Adult↗
PubMed1999

The relationship between a polymorphism in CYP17 with plasma hormone levels and breast cancer.

The A2 allele of CYP17 has been associated with polycystic ovarian syndrome, elevated levels of certain steroid hormones in premenopausal women, and increased breast cancer risk. We prospectively assessed the association between the A2 allele of CYP17 and breast cancer risk in a case-control study nested within the Nurses' Health Study cohort. We also evaluated associations between this CYP17 genotype and plasma steroid hormone levels among postmenopausal controls not using hormone replacement to assess the biological significance of this genetic variant. Women with the A2 allele were not at an increased risk of incident breast cancer [OR (odds ratio), 0.85; 95% CI (confidence interval), 0.65-1.12] or advanced breast cancer (OR, 0.84; 95% CI, 0.54-1.32). We did observe evidence that the inverse association of late age at menarche with breast cancer may be modified by the CYP17 A2 allele. The protective effect of later age at menarche was only observed among women without the A2 allele (A1/A1 genotype: for age at menarche > or =13 versus <13; OR, 0.57; 95% CI, 0.36-0.90; A1/A2 and A2/A2 genotypes: OR, 1.05; 95% CI, 0.76-1.45; P for interaction = 0.07). Among controls, we found women with the A2/A2 genotype to have elevated levels of estrone (+14.3%, P = 0.01), estradiol (+13.8%, P = 0.08), testosterone (+8.6%, P = 0.34), androstenedione (+17.1%, P = 0.06), dehydroepiandrosterone (+14.4%, P = 0.02), and dehydroepiandrosterone sulfate (+7.2%, P = 0.26) compared with women with the A1/A1 genotype. These data suggest that the A2 allele of CYP17 modifies endogenous hormone levels, but is not a strong independent risk factor for breast cancer.

Adult↗
PubMed1999

Dietary fiber and the risk of colorectal cancer and adenoma in women.

BACKGROUND: A high intake of dietary fiber has been thought to reduce the risk of colorectal cancer and adenoma. METHODS: We conducted a prospective study of 88,757 women, who were 34 to 59 years old and had no history of cancer, inflammatory bowel disease, or familial polyposis, who completed a dietary questionnaire in 1980. During a 16-year follow-up period, 787 cases of colorectal cancer were documented. In addition, 1012 patients with adenomas of the distal colon and rectum were found among 27,530 participants who underwent endoscopy during the follow-up period. RESULTS: After adjustment for age, established risk factors, and total energy intake, we found no association between the intake of dietary fiber and the risk of colorectal cancer; the relative risk for the highest as compared with the lowest quintile group with respect to fiber intake was 0.95 (95 percent confidence interval, 0.73 to 1.25). No protective effect of dietary fiber was observed when we omitted, adjustment for total energy intake, when events during the first six years of follow-up were excluded, or when we excluded women who altered their fiber intake during the follow-up period. No significant association between fiber intake and the risk of colorectal adenoma was found. CONCLUSIONS: Our data do not support the existence of an important protective effect of dietary fiber against colorectal cancer or adenoma.

Adenoma↗
PubMed1999

N-acetyl transferase 2 genotypes, meat intake and breast cancer risk.

Heterocyclic amines (HAs) are carcinogens produced by high-temperature cooking of meat and animal protein; metabolism of HA is influenced by polymorphisms in the N-acetyltransferase-2 (NAT-2) gene. Data from a variety of sources suggest that HA may play a role in human carcinogenesis. We examined the associations between meat intake and cooking method, acetylator genotype and breast cancer risk in a sub-cohort of 32,826 women in the Nurses' Health Study who gave a blood sample in 1989-1990. Women who were diagnosed with breast cancer (n = 466) after blood draw and prior to June 1, 1994, were matched to 466 controls. Overall, rapid acetylators were not at increased risk of breast cancer compared with slow acetylators (multivariate OR = 1.1, 95% CI 0.8-1.5), and there were no associations between meat intake or cooking method of meat and breast cancer risk. Rapid acetylators with the highest red meat intake (one or more servings per day) were not at increased risk of breast cancer compared with slow acetylators with the lowest red meat intake (OR = 1.1, 95% CI 0.7-1.8). Frequent intake of charred meat among rapid acetylators (one or more times per week) was not associated with increased risk (OR = 1.2, 95% CI 0.6-2.3) compared with slow acetylators who ate charred meat less than once per month. We observed no significant associations for rapid acetylators who frequently consumed beef, pork or lamb cooked with high-temperature cooking methods, such as barbecuing (OR = 0.9, 95% CI 0.4-1.9) or roasting (OR = 0.9, 95% CI 0.5-1.6). Our data suggest that HAs may not be a major cause of breast cancer, although we cannot exclude misclassification of HA intake as the reason for the lack of association. We observed no evidence of differential susceptibility to these exposures by NAT2 genotype.

Animals↗
PubMed1999

Risk factors for cervical squamous intraepithelial lesions among HIV-1 seropositive women in Dar es Salaam, Tanzania.

OBJECTIVES: To determine the prevalence and risk factors for cervical squamous intraepithelial lesions (SIL) among HIV-infected women in Dar es Salaam, Tanzania. METHODS: Between July 1996 and December 1997 we interviewed 691 HIV-infected women to obtain information about risk factors for SIL. Cervical smears and samples for lymphocyte subsets and sexually transmitted diseases (STD) diagnosis were collected. RESULTS: The prevalence of SIL was 2.9% (20/686) (95% CI = 1.7-4.2%). Eleven women had low-grade SIL while nine women had high-grade SIL. The number of lifetime sexual partners and live births was associated with a marginally non-significant increased risk of SIL. The risk of SIL was significantly increased among women with CD4+ cell count < 200/mm3 (multivariate odds ratio (OR) = 6.15, 95% CI = 1.19-41.37) and decreased by 68% for each 5-cm increase in mid-upper arm circumference (multivariate OR = 0.32, 95% CI = 0.10-0.93). CONCLUSIONS: HIV-related immunosuppression and wasting and long-term sexual behavior were the major determinants of SIL in this population. Federation of Gynecology and Obstetrics.

Adolescent↗
PubMed1999

High body mass index and hypercholesterolemia: risk of hypertensive disorders of pregnancy.

OBJECTIVE: To examine the relationship between pregravid body mass index (BMI), elevated cholesterol level, and the development of hypertensive disorders of pregnancy. METHODS: We studied 15,262 women who gave birth between 1991 and 1995. Pregravid exposures including BMI and self-reported history of elevated cholesterol were ascertained by biennial mailed questionnaires. Gestational hypertension or preeclampsia was confirmed by medical record review according to standard criteria. Proportional hazards analysis was used to adjust for potential confounding variables. RESULTS: We confirmed 216 cases of gestational hypertension and 86 cases of preeclampsia. The risk of gestational hypertension increased as pregravid BMI increased (P < .01). Compared with women with a pregravid BMI of 21-22.9 kg/m2, the relative risk (RR) of gestational hypertension was 1.6 (95% confidence interval [CI] 1.0, 2.3) for women with BMI of 23-24.9 kg/m2, 2.0 (95% CI 1.3, 3.0) for BMI 25-29.9 kg/m2, and 2.6 (95% CI 1.6, 4.4) for BMI over 30 kg/m2. Leaner women (BMI less than 21 kg/m2) had a reduced risk (RR 0.7, 95% CI 0.4, 1.0). For preeclampsia, the RR of women with pregravid BMI over 30 kg/m2 was 2.1 (95% CI 1.0, 4.6) (P for trend 0.09). A history of elevated cholesterol was not associated with the risk of gestational hypertension (RR 0.9, 95% CI, 0.6, 1.4). In contrast, the RR of preeclampsia in women with a history of elevated cholesterol was 2.0 (95% CI 1.2, 3.3). CONCLUSION: Pregravid BMI and hypercholesterolemia could identify women at higher risk for hypertensive disorders during pregnancy.

Adult↗
PubMed1999

Rationale and design of the Tanzania Vitamin and HIV Infection Trial.

We present the rationale and design of a randomized, double-blind, placebo-controlled trial of vitamin supplements among HIV-positive pregnant women in Dar es Salaam, Tanzania. Higher levels of intake of vitamins A, B, C, and E may decrease the risk of vertical transmission and progression of HIV infection by enhancing maternal and infant immune function; by reducing viral load in the blood, breast milk, or lower genital tract secretions; and/or by strengthening the placental barrier to infection. Eligible pregnant women were randomized to receive vitamin A, multivitamins excluding A, vitamin A and multivitamins, or placebo. The main endpoints include vertical transmission of HIV infection, as assessed by examination of infection in infants using polymerase chain reaction (PCR), and progression of HIV disease as measured by the WHO clinical staging system. Over a period of 2 years, 13,876 women were tested for HIV infection, with appropriate pre- and posttest counseling, to enroll 1085 consenting HIV-positive women. The trial assesses women and their children once a month for a minimum of 18 months after delivery or up to the end of this 5-year study. We examine recruitment strategies and means of enhancing cohort retention in long-term follow-up. We assess compliance with the use of supplements by direct questioning, by counting pills, and biochemically by using serum beta-carotene and urine riboflavin levels. Briefly, we discuss ethical issues related to the conduct of AIDS prevention trials in this setting. In sub-Saharan Africa, most HIV-infected persons lack access to the relevant antiretroviral and prophylactic drugs, and the region urgently needs low-cost treatments and preventive strategies. The Tanzania trial should provide valuable data to address the effect of vitamin supplements in the transmission and progression of HIV infection.

Child, Preschool↗
PubMed1999

Prospective study of smoking, antioxidant intake, and lung cancer in middle-aged women (USA).

BACKGROUND: Although substantial evidence suggests that higher intake of fruits and vegetables can reduce the adverse impact of smoking on lung cancer risk, great uncertainty exists regarding the specific foods and their constituents that are protective. We therefore examine prospectively the relation between cigarette smoking and lung cancer incidence among women, and quantify the associations between dietary antioxidants, other nutrients, and lung cancer risk. METHODS: In a 16-year prospective cohort study (the Nurses' Health Study), 593 cases of lung cancer were confirmed during 1,793,327 person-years of follow-up. Dietary data, including vitamin supplement use and food intake, were collected in 1980 using a validated semiquantitative food frequency questionnaire. RESULTS: The risk of lung cancer increased with the number of cigarettes smoked and with early onset of cigarette smoking. The risk decreased rapidly with the discontinuation of smoking but took 15 years to fall to about the level of risk for women who had never smoked. Dietary intake of fat was not related to the risk of lung cancer. Although beta-carotene intake was not related to risk, intake of carrots showed a strong inverse relation: women who reported consuming five or more carrots per week had a relative risk of 0.4 (95% CI = 0.2-0.8) compared with the risk for women who never ate carrots. CONCLUSIONS: Smoking is the most important risk factor for lung cancer in women, as it is in men. Higher vegetable consumption, particularly of carrots, may significantly reduce the risk of lung cancer, but dietary modification cannot be considered a substitute for smoking prevention and cessation.

Adult↗