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D J Hunter

Publications and source records attributed to D J Hunter.

At least 199 records · Page 11Linked to original sources
PubMed1996

Self-reported birthweight and history of having been breastfed among younger women: an assessment of validity.

BACKGROUND: Recent evidence suggests potential associations between birthweight and infant feeding history and risk of a variety of health outcomes during adulthood. Because studies may rely on self-reported birthweight and infant feeding history, it is important to assess the validity of this information. METHODS: The authors compared birthweights reported by a sample of 538 women, 27-44 years of age, participating in the Nurses' Healthy Study II (NHSII) cohort, with birthweights recalled by their mothers and with those from state birth records. In addition, we compared participants' self-reported history of having breastfed with their breastfeeding history reported by their mothers. RESULTS: For birthweight, the correlation between reports by the cohort participants and by their mothers was high (Spearman r = 0.75). Compared with weights recorded on state birth records, correlations were 0.74 for reports by cohort participants and 0.85 for reports by their mothers. When comparing NHSII participants' self-report of ever having been breastfed with their mothers' report, sensitivity was 82% and specificity was 86%. For duration of breastfeeding, the Spearman correlation between mother and daughter reports was 0.74. In analyses stratified by four ethnic groups (African-American, Asian, Caucasian, and Hispanic) we observed substantial differences in distribution of birthweight and breastfeeding patterns; however, the degree of validity in reporting them was similar. CONCLUSION: The validity of self-reported birthweight and breastfeeding history by these middle-aged women appears to be high.

Adult↗
PubMed1996

Variability in diagnostic evaluation and criteria for gestational diabetes.

OBJECTIVE: To determine the frequency of screening for gestational diabetes mellitus (GDM) among a population receiving regular prenatal care and to assess the extent to which National Diabetes Data Group (NDDG) criteria for the diagnosis of GDM are used by practicing obstetricians. RESEARCH DESIGN AND METHODS: We studied participants in the Nurses' Health Study II, a large prospective cohort study of 116,678 nurses aged 25-42 years in 1989. A total of 422 women who reported a first diagnosis of GDM between 1989 and 1991 were sent supplementary questionnaires regarding diagnosis and treatment, and medical records were requested for a subset of 120 to validate self-reported GDM and assess criteria used for diagnosis. A sample of 100 women who reported a pregnancy not complicated by GDM were sent questionnaires addressing GDM screening and prenatal care. RESULTS: Among a sample of 93 women who reported a pregnancy not complicated by GDM and responded to the supplementary questionnaire, 16 (17%) reported no glucose loading test; 69% of unscreened women had one or more risk factors for GDM. Among a sample of 114 women who self-reported GDM in a singleton pregnancy and whose medical records were available for review, a physician diagnosis of GDM was confirmed in 107 (94%). Records and supplementary questionnaires indicated that oral glucose tolerance tests (OGTTs) were performed in 96 (86%) of these women. Of women with a physician diagnosis of GDM whose OGTT results were available, 25% failed to meet NDDG criteria for this diagnosis, although all had evidence of abnormal glucose homeostasis. CONCLUSIONS: Screening for GDM is not universal, even among a group of health professionals in whom screening prevalence is likely to be higher than in the general population. Diagnostic criteria for GDM among obstetricians in practice remain nonstandard despite NDDG recommendations. Better understanding of the implications of differing degrees of glucose intolerance and of varying GDM screening and management strategies is required to make policy recommendations for appropriate and cost-effective care.

Adult↗
PubMed1996

Prevalence of urinary symptoms and other urological conditions in Spanish men 50 years old or older.

PURPOSE: We determined the prevalence of lower urinary tract symptoms and other urological conditions in Spanish men. MATERIALS AND METHODS: A cross-sectional population survey of 2,002 men 50 years old or older was done using interviewers in the autonomous community of Madrid. The main outcome measures were the self-reported International Prostate Symptom Score, and acute retention, incontinence, renal failure, hematuria, urinary infection and bladder stones. RESULTS: The estimated response rate among eligible responders was 68.1%. The prevalence of moderate or severe symptoms was 30.4%, which increased with age. Of men with moderate or severe symptoms 26.5% reported that the symptoms were a medium or great problem and 5.4% reported that the symptoms interfered with daily activities at least sometimes. The prevalence of other urological conditions related to the prostate was 5.1% for acute retention, 1.2% for current use of a catheter, 6.1% for incontinence, 2.4% for renal failure, 2.5% for hematuria, 5.2% for urinary infection and 0.7% for bladder stones. CONCLUSIONS: The prevalence of moderate or severe symptoms is greater than reported in most other studies. Although Spanish men with moderate or severe symptoms report similar levels of bothersomeness, the impact of the symptoms in terms of interference with daily activities and perception of the future is less than that in other countries.

Aged↗
PubMed1995

Body weight and mortality among women.

BACKGROUND: The relation between body weight and overall mortality remains controversial despite considerable investigation. METHODS: We examined the association between body-mass index (defined as the weight in kilograms divided by the square of the height in meters) and both overall mortality and mortality from specific causes in a cohort of 115,195 U.S. women enrolled in the prospective Nurses' Health Study. These women were 30 to 55 years of age and free of known cardiovascular disease and cancer in 1976. During 16 years of follow-up, we documented 4726 deaths, of which 881 were from cardiovascular disease, 2586 from cancer, and 1259 from other causes. RESULTS: In analyses adjusted only for age, we observed a J-shaped relation between body-mass index and overall mortality. When women who had never smoked were examined separately, no increase in risk was observed among the leaner women, and a more direct relation between weight and mortality emerged (P for trend < 0.001). In multivariate analyses of women who had never smoked and had recently had stable weight, in which the first four years of follow-up were excluded, the relative risks of death from all causes for increasing categories of body-mass index were as follows: body-mass index < 19.0 (the reference category), relative risk = 1.0; 19.0 to 21.9, relative risk = 1.2; 22.0 to 24.9, relative risk = 1.2; 25.0 to 26.9, relative risk = 1.3; 27.0 to 28.9, relative risk = 1.6; 29.0 to 31.9, relative risk = 2.1; and > or = 32.0, relative risk = 2.2 (P for trend < 0.001). Among women with a body-mass index of 32.0 or higher who had never smoked, the relative risk of death from cardiovascular disease was 4.1 (95 percent confidence interval, 2.1 to 7.7), and that of death from cancer was 2.1 (95 percent confidence interval, 1.4 to 3.2), as compared with the risk among women with a body-mass index below 19.0. A weight gain of 10 kg (22 lb) or more since the age of 18 was associated with increased mortality in middle adulthood. CONCLUSIONS: Body weight and mortality from all causes were directly related among these middle-aged women. Lean women did not have excess mortality. The lowest mortality rate was observed among women who weighed at least 15 percent less than the U.S. average for women of similar age and among those whose weight had been stable since early adulthood.

Adult↗
PubMed1995

Aspirin and the risk of colorectal cancer in women.

BACKGROUND: Most data suggest that the regular use of aspirin reduces the risk of colorectal cancer, but some apparently conflicting evidence exists. The effects of the dose and the duration of aspirin consumption on the risk of colorectal cancer are not well understood. METHODS: We determined rates of colorectal cancer according to the number of consecutive years of regular aspirin use (defined as two or more tablets per week) among women in the Nurses' Health Study who reported regular aspirin use on three consecutive questionnaires (1980, 1982, and 1984) and compared the rates in this group with the rates among women who said they did not use aspirin. Cases of cancer occurring from 1984 through 1992 (the eight years after the 1984 questionnaire) were included. RESULTS: From 1984 through 1992, we documented 331 new cases of colorectal cancer during 551,651 person-years of follow-up. Women who consistently took two or more aspirin tablets per week had no appreciable reduction in the risk of colorectal cancer as compared with nonusers after four years (relative risk, 1.06; 95 percent confidence interval, 0.78 to 1.45) or after five to nine years (relative risk, 0.84; 95 percent confidence interval, 0.55 to 1.28). There was a slight reduction in risk among women who took aspirin for 10 to 19 years, but it was not statistically significant (relative risk, 0.70; 95 percent confidence interval, 0.41 to 1.20). However, there was a statistically significant reduction after 20 years of consistent use of aspirin (relative risk, 0.56; 95 percent confidence interval, 0.36 to 0.90; P for trend = 0.008). The maximal reduction in risk was observed among women who took four to six tablets per week; higher doses had a similar apparent benefit. Controlling for risk factors for colorectal cancer, including diet, did not change the results, and the earlier diagnosis and removal of colorectal adenomas among aspirin users did not account for the results. CONCLUSIONS: Regular aspirin use, at doses similar to those recommended for the prevention of cardiovascular disease, substantially reduces the risk of colorectal cancer. However, this benefit may not be evident until after at least a decade of regular aspirin consumption.

Adult↗
PubMed1995

Alcohol, height, and adiposity in relation to estrogen and prolactin levels in postmenopausal women.

BACKGROUND: Alcohol use, height, and postmenopausal adiposity have each been positively associated with postmenopausal breast cancer risk in most epidemiologic studies. The mechanism underlying these associations is unclear, although an effect of these factors on hormone levels has been hypothesized. Few previous studies have evaluated the relationship of either alcohol consumption or height with plasma hormone levels. A positive association between adiposity and plasma estrogen levels in postmenopausal women has been reported consistently. PURPOSE: Using archived frozen plasma samples and corresponding data from participants in the Nurses' Health Study, we determined plasma hormone levels and assessed these levels in relation to alcohol consumption, height, and adiposity among postmenopausal women. METHODS: Blood samples were collected from a subset of participants in the Nurses' Health Study in 1989 and 1990, then stored in liquid nitrogen. Hormone concentrations in 217 archived plasma samples (from healthy postmenopausal women) were analyzed in 1993. Spearman correlation coefficients were calculated to assess the linear association between alcohol consumption during the previous year (mean daily intake in grams per day ascertained from semiquantitative food-frequency questionnaires completed in 1990 or 1991), height, and adiposity (as measured by body mass index [BMI] in kg/m2, with weight reported at time of blood collection), and plasma hormone levels. Two-sided P values were also calculated. RESULTS: After controlling for age, height, smoking status, and BMI, alcohol consumption was positively associated with estrone sulfate concentrations (r = .17; P = .02); no statistically significant association was noted for the other plasma hormones measured. Mean plasma estrone sulfate levels were 159 pg/mL in women who reported no alcohol use versus 211 pg/mL in women consuming 30 g or more of alcohol per day. After adjusting for the other covariates, we observed a strong positive correlation between BMI and plasma estrogens (r ranging from .37 for estrone and estrone sulfate to .63 for bioavailable estradiol, with all P values < or = .01; prolactin was the only hormone unassociated with BMI, r = -.01). Height was unrelated to either plasma estrogens or prolactin. CONCLUSIONS: BMI and alcohol use were positively associated with postmenopausal plasma estrogen and estrone sulfate levels, respectively. IMPLICATIONS: The association of alcohol consumption and postmenopausal obesity with subsequent breast cancer risk might be mediated, at least in part, through an influence on postmenopausal plasma estrogen levels. Additional studies are needed to further quantify the relationship between alcohol consumption and plasma hormone levels and to elucidate the physiologic basis for this association.

Adult↗
PubMed1995

A prospective study of incident squamous cell carcinoma of the skin in the nurses' health study.

BACKGROUND: Few epidemiologic studies are available that quantify the magnitude of the risk of squamous cell carcinoma (SCC) of the skin associated with sun exposure and related factors such as skin type. In addition, several studies have found an association between cigarette smoking and SCC. PURPOSE: We prospectively examined the risk of developing SCC in relation to phenotype and the effects of sun exposure, as well as to cigarette smoking and other factors, during 8 years of follow-up in a cohort of 107,900 predominantly white women aged 30-55 years at base line in 1976. METHODS: Questionnaires regarding medical history and health-related variables were sent to Nurses' Health Study participants every 2 years, beginning in 1976. Information on constitutional factors (natural hair color, childhood and adolescent tendency to sunburn and tan, and lifetime number of severe sunburns), lifestyle factors (regular time spent outdoors in the summer and sunscreen use), the state lived in at birth and at ages 15 and 30 years, and cigarette smoking habits were ascertained by questionnaire. A total of 197 women with first-incident, histologically confirmed, invasive SCCs that were diagnosed from 1982 to 1990 were included in this analysis. Multivariate analysis using proportional hazards models was used to calculate the relative risks (RRs) and corresponding 95% confidence intervals (CIs), with adjustment for confounders. RESULTS: The risk of SCC was increased in women living in California (RR = 1.8; 95% CI = 1.3-2.6) and Florida (RR = 2.1; 95% CI = 1.1-3.9) at base line, compared with those living in the northeastern states. This risk was higher for women living in those states at birth and at 15 years of age (RR = 2.5; 95% CI = 1.4-4.4 for California and RR = 3.0; 95% CI = 0.7-1.2 for Florida). Red (RR = 2.0; 95% CI = 1.1-3.7) and light brown (RR = 1.7; 95% CI = 1.2-2.4) hair colors were associated with an increased risk of SCC, compared with dark brown hair. After adjusting for the number of sunburns, women who tended to burn after 2 or more hours of sun exposure as children had a slightly higher risk of SCC than those who never burned (RR = 1.5; 95% CI = 0.9-2.5 for burn and RR = 1.1; 95% CI = 0.6-2.0 for painful burn), although the actual number of severe burns appeared to be a more important factor (RR = 2.4; 95% CI = 1.5-4.0 for six or more burns). Finally, current cigarette smokers showed a 50% increase in the risk of SCC compared with never smokers (RR = 1.5; 95% CI = 1.1-2.1). CONCLUSION: Exposure to the sun leading to sunburn, particularly at early ages, should be avoided to decrease the risk of incident SCC.

Adult↗
PubMed1995

A prospective study of reproductive factors and risk of epithelial ovarian cancer.

BACKGROUND: Parity and long term use of oral contraceptives have been associated consistently with a decreased risk of ovarian cancer. However, previous reports of the relationship of other reproductive factors (time since first use or last use of oral contraceptives, age at menarche or menopause, age at first birth) with ovarian cancer have been inconsistent. METHODS: The authors studied these relationships in the Nurses' Health Study, a prospective cohort study of 121,700 female registered nurses aged 30-55 years in 1976 when the study began. From 1976 to 1988, 260 cases of confirmed epithelial ovarian cancer occurred among 1.2 million person-years of follow-up. RESULTS: A statistically significant inverse association was observed between parity and ovarian cancer risk (relative risk [RR] = 0.84; 95% confidence interval [CI] = 0.77-0.91 per pregnancy); age at first birth was not associated independently with risk. In age-adjusted analyses, a significant inverse association was noted between long term use of oral contraceptives and ovarian cancer, which was no longer significant after controlling for other ovarian cancer risk factors (RR with > or = 5 years' use: 0.65; 95% CI = 0.40-1.05). After control for duration of use, a weak nonsignificant inverse association was observed with time since first oral contraceptive use and no independent effect of time since last use. Neither age at menarche nor age at menopause was associated significantly with ovarian cancer risk. CONCLUSIONS: In this large prospective study, parity was the only reproductive factor that had a substantial independent association with ovarian cancer. Long term oral contraceptive use also appeared to have an inverse relationship with ovarian cancer, although this association was of borderline significance (P = 0.11) after adjustment for other risk factors.

Age Factors↗
PubMed1995

Silicone breast implants and the risk of connective-tissue diseases and symptoms.

BACKGROUND: Silicone breast implants have been linked to a variety of illnesses, the most controversial of which are connective-tissue diseases and symptoms. To study this relation, we analyzed data from 14 years of follow-up of the Nurses' Health Study cohort. METHODS: Women who were free from connective-tissue disease in June 1976 were followed through May 31, 1990, before there was widespread media coverage of the possible association of breast implants and connective-tissue diseases. Information was collected through biennial and supplementary mailed questionnaires and blinded reviews of medical records with the use of standardized criteria. Relative risk, the measure of association, was defined as the incidence rate of connective-tissue disease among women with breast implants divided by the corresponding incidence rate among women without breast implants. RESULTS: Among 87,501 women who were eligible for follow-up, 516 were confirmed as having definite connective-tissue diseases and 1183 as having breast implants (of which 876 were silicone-gel-filled, 170 saline-filled, 67 double-lumen, 14 polyurethane-coated, and 56 of unknown type). The mean (+/- SD) period of follow-up after surgery was 9.9 +/- 6.4 years (range, 1 month to 40.5 years). Three of the patients with definite connective-tissue disease--all had rheumatoid arthritis--had implants (one silicone-gel-filled, one saline-filled, and one double-lumen). The age-adjusted relative risk of a definite connective-tissue disease among women with any type of implant was 0.6 (95 percent confidence interval, 0.2 to 2.0), as compared with women without implants. For women with silicon-gel-filled implants, the comparable relative risk was 0.3 (95 percent confidence interval, 0 to 1.9). The relative risk of self-reported signs or symptoms of connective-tissue disease for women with implants was 1.5 (95 percent confidence interval, 0.9 to 2.4); the risk of having any 1 of 41 signs, symptoms, or laboratory features of connective-tissue disease was 0.7 (95 percent confidence interval, 0.3 to 1.6). CONCLUSIONS: In a large cohort study, we did not find an association between silicone breast implants and connective-tissue diseases, defined according to a variety of standardized criteria, or signs and symptoms of these diseases.

Adult↗
PubMed1995

The use of estrogens and progestins and the risk of breast cancer in postmenopausal women.

BACKGROUND: The effect of adding progestins to estrogen therapy on the risk of breast cancer in postmenopausal women is controversial. METHODS: To quantify the relation between the use of hormones and the risk of breast cancer in postmenopausal women, we extended our follow-up of the participants in the Nurses' Health Study to 1992. The women were asked to complete questionnaires every two years to update information on their menopausal status, use of estrogen and progestin preparations, and any diagnosis of breast cancer. During 725,550 person-years of follow-up, we documented 1935 cases of newly diagnosed invasive breast cancer. RESULTS: The risk of breast cancer was significantly increased among women who were currently using estrogen alone (relative risk, 1.32; 95 percent confidence interval, 1.14 to 1.54) or estrogen plus progestin (relative risk, 1.41; 95 percent confidence interval, 1.15 to 1.74), as compared with postmenopausal women who had never used hormones. Women currently taking hormones who had used such therapy for 5 to 9 years had an adjusted relative risk of breast cancer of 1.46 (95 percent confidence interval, 1.22 to 1.74), as did those currently using hormones who had done so for a total of 10 or more years (relative risk, 1.46; 95 percent confidence interval, 1.20 to 1.76). The increased risk of breast cancer associated with five or more years of postmenopausal hormone therapy was greater among older women (relative risk for women 60 to 64 years old, 1.71; 95 percent confidence interval, 1.34 to 2.18). The relative risk of death due to breast cancer was 1.45 (95 percent confidence interval, 1.01 to 2.09) among women who had taken estrogen for five or more years. CONCLUSIONS: The addition of progestins to estrogen therapy does not reduce the risk of breast cancer among postmenopausal women. The substantial increase in the risk of breast cancer among older women who take hormones suggests that the trade-offs between risks and benefits should be carefully assessed.

Aged↗
PubMed1995

Alcohol consumption and mortality among women.

BACKGROUND: Studies in men suggest that light-to-moderate alcohol intake is associated with a reduction in overall mortality, due primarily to a reduced risk of coronary heart disease. Among women with similar levels of alcohol consumption, an increased risk of breast cancer has been noted that complicates the balance of risks and benefits. METHODS: We conducted a prospective study among 85,709 women, 34 to 59 years of age and without a history of myocardial infarction, angina, stroke, or cancer, who completed a dietary questionnaire in 1980. During the 12-year follow-up period, 2658 deaths were documented. RESULTS: The relative risks of death in drinkers as compared with nondrinkers were 0.83 (95 percent confidence interval, 0.74 to 0.93) for women who consumed 1.5 to 4.9 g of alcohol per day (one to three drinks per week), 0.88 (95 percent confidence interval, 0.80 to 0.98) for those who consumed 5.0 to 29.9 g per day, and 1.19 (95 percent confidence interval, 1.02 to 1.38) for those who consumed 30 g or more per day, after adjustment for other predictors of mortality. Light-to-moderate drinking (1.5 to 29.9 g per day) was associated with a decreased risk of death from cardiovascular disease; heavier drinking was associated with an increased risk of death from other causes, particularly breast cancer and cirrhosis. The benefit associated with light-to-moderate drinking was most apparent among women with risk factors for coronary heart disease and those 50 years of age or older. CONCLUSIONS: Among women, light-to-moderate alcohol consumption is associated with a reduced mortality rate, but this apparent survival benefit appears largely confined to women at greater risk for coronary heart disease.

Adult↗
PubMed1995

Prospective study of toenail selenium levels and cancer among women.

BACKGROUND: Inverse associations between selenium status and cancer risk have been observed in animal studies, ecologic studies, and some case-control and prospective studies. Whereas results of some prospective studies have suggested an overall inverse relationship between selenium levels and cancer, other prospective studies have failed to confirm this finding. Prospective data on women are particularly limited because fewer women than men have been studied prospectively. PURPOSE: The aim of this study was to prospectively examine the relationship between selenium levels in toenails (previously shown to reflect selenium intake) and incidence of cancer among women. METHODS: The Nurses' Health Study cohort began in 1976 with 121,700 female nurses aged 30-55 years living in 11 U.S. states. In 1982, we requested toenail clippings from the members of the cohort, and 62,641 participants with no history of cancer returned these clippings. During 41 months of follow-up, 503 cases of cancer other than breast cancer (results previously reported) or nonmelanoma skin cancer were analyzed. For each case patient, a control subject was chosen from women who remained free of diagnosed cancer, matched by age and by date of nail return. RESULTS: No inverse association was observed between selenium levels in toenails and cancer risk. The age- and smoking-adjusted relative risk (RR), comparing the highest with the lowest quintile of toenail selenium level, was 1.44 (95% confidence interval [CI] = 0.97-2.13), and the trend across quintiles was marginally significant (two-sided P = .06). Comparing the highest with the lowest decile, the RR (age- and smoking-adjusted) was 1.77 (95% CI = 1.04-3.02). When these data were combined with the data from 434 breast cancer case patients and their matched control subjects identified in parallel from this same cohort, the RR comparing the highest with the lowest quintile was 1.24 (95% CI = 0.93-1.65). Toenail selenium level was not inversely associated with cancer at any major site, including uterine cancer, colorectal cancer, melanoma, ovarian cancer, or lung cancer (after adjusting for smoking); in fact, nonsignificant positive associations were observed at several sites. CONCLUSIONS: Toenail selenium levels were not inversely associated with cancer risk in this study. IMPLICATIONS: These data, in conjunction with previous findings of no association between toenail selenium status and breast cancer risk, strongly suggest that higher selenium intake within the range consumed by most U.S. women (as reflected by toenail selenium levels) is not protective against overall cancer incidence in women.

Adult↗
PubMed1995

Postmenopausal estrogen therapy and the risk for developing systemic lupus erythematosus.

OBJECTIVE: To examine the relation between postmenopausal hormone use and development of systemic lupus erythematosus. DESIGN: Prospective cohort study. SETTING: Nurses' Health Study. PATIENTS: 69,435 women aged 30 to 55 years in 1976 who reported that they had completed menopause and did not have systemic lupus erythematosus or any connective tissue disease were followed every 2 years from 1976 to 1990. These women were classified as never- or ever-(current and past) users of postmenopausal hormones. MEASUREMENTS: Incidence rates of systemic lupus erythematosus and classification criteria from the American College of Rheumatology that were confirmed by chart review. RESULTS: With never-users of postmenopausal hormones as the reference group, age-adjusted relative risks for systemic lupus erythematosus (n = 45 women) were 2.1 (95% CI, 1.1 to 4.0) for ever-users, 2.5 (CI, 1.2 to 5.0) for current users, and 1.8 (CI, 0.8 to 4.1) for past users. A proportional increase in the risk for systemic lupus erythematosus was observed that was related to the duration of use of postmenopausal hormones (test for trend, P = 0.011). CONCLUSIONS: Postmenopausal hormone therapy is associated with an increased risk for developing systemic lupus erythematosus.

Adult↗
PubMed1995

Reproductive factors and family history of breast cancer in relation to plasma estrogen and prolactin levels in postmenopausal women in the Nurses' Health Study (United States).

Parity, age at first birth, age at menarche, and a family history of breast cancer have each been associated consistently with breast cancer risk. Whether this increase in risk is mediated, at least in part, through changes in endogenous hormone levels is unclear. We conducted a cross-sectional study of the relationships between these factors and plasma hormone levels in 216 healthy postmenopausal women in the Nurses' Health Study (United States). The hormones evaluated were estradiol, percent and total free estradiol, percent and total bioavailable estradiol, estrone, estrone sulfate, and prolactin. After controlling for age, body mass index (weight/height2), and alcohol use, we observed inverse associations between estrone sulfate and parity (r = -0.15, P = 0.03) and between percent bioavailable estradiol and age at first birth (r = -0.17, P = 0.02). Although women with a family history of breast cancer tended to have higher estrogen levels compared with women without such history, the differences were not statistically significant. Age at menarche was not related significantly to any of the hormones. These data provide some additional evidence that the inverse relationship observed between parity and breast cancer risk may be mediated, at least in part, through decreased estrogen levels. Our data do not support a substantial influence of either family history of breast cancer or age at menarche on postmenopausal estrogen or prolactin levels.

Adult↗