Biomedical subjects

G A Colditz

Publications and source records attributed to G A Colditz.

At least 433 records · Page 24Linked to original sources

PubMed1990

Risk factors for basal cell carcinoma in a prospective cohort of women.

In a prospective study of self-reported demographic, constitutional, and life-style factors in relation to basal cell carcinoma of the skin, we followed a cohort of 73,366 nurses in the United States who were 34 to 59 years of age in 1980 and who had no previous skin or other cancer. In 4 years of follow-up, compared with women living in the Northeast, women residing in California (age-adjusted relative risk [RR] = 1.57; 95% confidence interval [CI] = 1.30 to 1.89) and Florida (RR = 2.12; 95% CI = 1.54 to 2.92) were more likely to develop basal cell carcinoma. Compared with women having naturally dark brown hair, the age-adjusted relative risk of basal cell carcinoma was increased among women with red (RR = 2.45; 95% CI = 1.89 to 3.19), blonde (RR = 1.37; 95% CI = 1.09 to 1.71), or light brown hair (RR = 1.27; 95% CI = 1.08 to 1.49) and was decreased among women with black hair (RR = 0.66; 95% CI = 0.41 to 1.06). Risk was positively associated in a dose-response manner both with tendency to sunburn as a child or adolescent and with lifetime number of severe and painful sunburns on the face or arms. These risk factors remained significant predictors of disease when included simultaneously in multivariate analyses. Tendency to tan was associated with decreased risk, although this risk was not significant after controlling for the other constitutional determinants and region. Cigarette smoking did not alter the risk of basal cell carcinoma. These prospective data emphasize the importance of sunlight, and skin response to sunlight, as determinants of basal cell carcinoma among women.

Adult↗

PubMed1990

Patterns of weight change and their relation to diet in a cohort of healthy women.

Patterns of weight change for 31,940 non-smoking women aged 30-55 y in 1976 were examined for 8 y of follow-up. Each woman reported her weight every 2 y on questionnaires, and diet was assessed in 1980 with a semiquantitative food frequency questionnaire. Self-reported weight was highly correlated over time, decreasing from r = 0.95 over 2 y to r = 0.89 over 8 y. Weight gain was inversely related to age (r = -0.06). Weight change in a given 2-y interval was inversely related to change in weight over the subsequent 2 y (r = -0.30). Age, relative weight, and prior weight change were stronger predictors of recent weight change than were intake patterns of specific nutrients. Recent prior weight change was the strongest predictor of subsequent weight change. In a population of free-living women, prior weight loss and younger age are far stronger predictors of subsequent weight gain than are the qualitative aspects of diet.

Adult↗

PubMed1990

Dietary predictors of symptom-associated gallstones in middle-aged women.

In 1980, 88,837 women aged 34-59 y completed a semiquantitative food frequency questionnaire and were followed for 4 y. Four hundred thirty-three women reported a cholecystectomy for recent cholecystitis, and 179 reported unremoved, newly symptomatic gallstones diagnosed by ultrasound or x ray. Among the 59,306 women with Quetelet's index of relative weight less than 25 kg/m2, inverse associations were observed between intakes of vegetable fat and vegetable protein and the risk of reportedly symptomatic gallastones, after adjusting for age, Quetelet's index in 1980, weight change between 1976 and 1980, energy intake, and alcohol intake. The relative risk in the highest quintile of vegetable fat intake, as compared with the lowest quintile, was 0.6 [95% confidence interval (CI), 0.4-0.9], and the corresponding relative risk for vegetable protein intake was 0.7 (95% CI, 0.6-0.9). No significant associations were found with energy-adjusted intakes of cholesterol, animal fat, animal protein, carbohydrate, or sucrose.

Adult↗

PubMed1990

Effectiveness of various mailing strategies among nonrespondents in a prospective cohort study.

Measures of association in prospective studies can be distorted by incomplete follow-up. Various mailing strategies were used to contact 12,233 cohort members of the Health Professionals Follow-up Study who had not responded to three successive bulk-rate mailings. Response rates were highest, 79.5% overall, from participants who were sent a certified mailing in phase 1 (63.2%), followed by a repeat certified mailing to nonrespondents (44.3%). Although altering the physical appearance of the envelope and using other postal rates were tested, certified mail was the most effective approach for reaching study members who were nonrespondents to a mailed questionnaire.

Adult↗

PubMed1990

Predictors of selenium concentration in human toenails.

To assess the validity of the selenium concentration in human toenails as a measure of selenium intake and to determine other correlates of toenail selenium level, the authors examined the predictors of toenail selenium within two subgroups of a large cohort study of US women. Mean toenail selenium was higher among 38 consumers of selenium supplements (0.904 micrograms/g, standard deviation (SD) 0.217) than among 96 nonusers (0.748 micrograms/g, SD 0.149; p less than 0.001), and a dose-response relation was observed among supplement users (Spearman's r = 0.32; p = 0.05). In a second subgroup of 677 women, selenium supplement use was also associated with higher mean toenail selenium (0.906 micrograms/g, SD 0.214, among 18 users and 0.801 micrograms/g, SD 0.148, among 659 nonusers; p = 0.02), and the dose-response relation was also significant (Spearman's r = 0.50; p = 0.03). The geographic variation in toenail selenium levels was consistent with the geographic distribution of selenium in forage crops. Toenail selenium declined with age and was significantly reduced among cigarette smokers (mean = 0.746, SD 0.124, among 146 current smokers and mean = 0.817, SD 0.159, among 311 never smokers; p less than 0.001) but was not materially affected by alcohol consumption. A dietary selenium score calculated from a food frequency questionnaire failed to predict toenail selenium level, demonstrating the suspected inability of diet questionnaires to measure individual selenium intake because of the highly variable selenium composition of different samples of the same food.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Lactation and risk of breast cancer in a cohort of US women.

The relation between lactation and risk of breast cancer was examined in a cohort of 89,413 parous female US registered nurses aged 30-55 years and free from cancer in 1976 who provided information on total duration of lactation in 1986. Between 1976 and 1986, 1,262 cases of breast cancer occurred during 785,958 person-years of follow-up. There was no independent association between lactation and the risk of breast cancer. After adjustment for age and parity, compared with women who had never lactated, the relative risks (and 95% confidence intervals (CI] were 0.95 (95% CI 0.84-1.08) for women with less than 7 months of lactation, 0.87 (95% CI 0.71-1.08) for 7-11 months, 0.94 (95% CI 0.77-1.14) for 12-23 months, and 0.98 (95% CI 0.76-1.28) for greater than or equal to 24 months (test for trend: z = -0.80, p = 0.42). The association did not differ by age or menopausal status. These results do not confirm reports that relatively short durations of lactation reduce the risk of breast cancer among younger women.

Adult↗

PubMed1990

Weight as a risk factor for clinical diabetes in women.

To determine the relation of body mass index (weight/height2) with the risk of clinical non-insulin-dependent diabetes, the authors analyzed data from a cohort of 113,861 US women aged 30-55 years in 1976. During 8 years of follow-up (826,010 person-years), 873 definite cases were identified among women initially free from diagnosed diabetes. Among women of average body mass index, 23-23.9 kg/m2, the relative risk was 3.6 times that of women having a body mass index less than 22 kg/m2. The risk continued to increase above this level of body mass index. The authors observed a much weaker positive association with weight at age 18, and this association was eliminated after adjustment for current body mass index. Thus, weight gain after age 18 was a major determinant of risk. For an increase of 20-35 kg, the relative risk was 11.3, and for an increase of more than 35 kg, the relative risk was 17.3. Adjusting for family history did not appreciably alter the strong relation observed among women at average levels of body mass index. These data indicate that, at even average weight, women are at increased risk of clinical non-insulin-dependent diabetes and that the relation between body mass index and risk of diabetes is continuous.

Adult↗

PubMed1990

A meta-analysis of physical activity in the prevention of coronary heart disease.

Evidence for an independent role of increased physical activity in the primary prevention of coronary heart disease has grown in recent years. The authors apply the techniques of meta-analysis to data extracted from the published literature by Powell et al. (Ann Rev Public Health 1987;8:253-87), as well as more recent studies addressing this relation, in order to make formal quantitative statements and to explore features of study design that influence the observed relation between physical activity and coronary heart disease risk. They find, for example, a summary relative risk of death from coronary heart disease of 1.9 (95% confidence interval 1.6-2.2) for sedentary compared with active occupations. The authors also find that methodologically stronger studies tend to show a larger benefit of physical activity than less well-designed studies.

Cohort Studies↗

PubMed1990

Reproductive factors, smoking, and the risk for rheumatoid arthritis.

Risk factors for rheumatoid arthritis were examined in a cohort of 121,700 female nurses aged 30-55, followed in the Nurses' Health Study. Baseline information on reproductive variables, cigarette smoking, obesity, and other variables was obtained in 1976 and updated every 2 years. Cases of rheumatoid arthritis were defined by standardized questionnaire and review of medical records. During 883,187 person-years of follow-up, 217 new cases of rheumatoid arthritis were identified (115 had definite rheumatoid arthritis and 102 had "undifferentiated polyarthritis"). When compared with women who experienced menarche at age 13 years, the age-adjusted relative risk of rheumatoid arthritis among women with early menarche was 1.9 (95% confidence interval, 0.9-2.4). There were, however, no significant associations between parity, age at birth of the first child, menopause, or obesity and the incidence of rheumatoid arthritis. Cigarette smokers had a slight apparent increase in the risk of rheumatoid arthritis. Among current smokers, the age-adjusted relative risk for RA rheumatoid arthritis was 1.3 (0.9-2.1); among former smokers, the relative risk was 1.5 (0.9-2.3).

Adult↗

PubMed1990

Validity of self-reported waist and hip circumferences in men and women.

Recent epidemiologic evidence indicates an association between fat distribution and many diseases. To assess the validity of circumference measurements obtained by self-report, the authors analyzed data from 123 men aged 40-75 years and 140 women aged 41-65 years, drawn from two large ongoing prospective studies. On mailed questionnaires, subjects were asked to measure and record their weight and waist and hip circumferences. These data were compared with standardized measurements taken approximately six months apart by technicians who visited participants at their homes. Crude Pearson correlations between self-reported waist circumferences and the average of two technician-measured waist circumferences were 0.95 for men and 0.89 for women. Similar correlations for hip measurements were 0.88 for men and 0.84 for women, and for waist-to-hip ratios, 0.69 for men and 0.70 for women. After adjusting for age and body mass index (kg/m2), correlations for waist-to-hip ratios were 0.55 for men and 0.58 for women. Correlations became stronger after correcting for random within-person variability from daily or seasonal fluctuations. Self-reported and measured weights were highly correlated: 0.97 for men and 0.97 for women. Self-reported waist, hip, and weight measurements appear reasonably valid. The moderate degree of measurement error for the ratio of self-reported waist and hip circumferences, however, implies that previously reported associations based on self-report of these measures may have been appreciably underestimated.

Adult↗

PubMed1990

The diagnostic value of upper gastrointestinal radiography.

We reviewed the indications for and results of 788 consecutive upper gastrointestinal radiographs (UGIs) performed for ambulatory patients. Sixty-three percent of tests were ordered for the evaluation of abdominal pain, dyspepsia, or esophageal reflux. Of these tests, only 4.8% yielded results of major clinical importance to patient management. The yield for patients greater than 50 years of age was greater than for patients less than 50, 6.9 versus 3.0% (p = 0.04). There was a significant increase in yield with increasing age (chi trend = 11.6, p less than 0.001). Among patients with an indication of esophageal reflux alone (n = 62), there were no patients younger than age 60 with a test result that would significantly affect therapy or outcome. Among patients evaluated for fecal occult blood or weight loss (n = 120), 11.7% of tests ordered showed a finding of major clinical importance. In this group, the yield was higher in those greater than or equal to 50 years of age than in those less than 50, 14.7 versus 6.7%, (p = 0.2). These results indicate that UGIs ordered to evaluate pain or symptoms of esophageal reflux in the absence of bleeding or weight loss rarely yield results that significantly influence therapy. Such patients may be best served by an initial trial of empiric therapy or some other test. The UGI has greatest value when indications for it include bleeding or weight loss.

Age Factors↗

PubMed1990

The risks and benefits of an Rx-to-OTC switch. The case of over-the-counter H2-blockers.

In recent years, many new over-the-counter (OTC) medications have resulted from the granting of OTC status by the U.S. Food and Drug Administration to drug entities that previously were available only by prescription (Rx). While the benefits to consumers of Rx-to-OTC switches may be substantial, they also involve some degree of risk, as usage typically expands and physician supervision diminishes. This study explores the potential utility of techniques of decision analysis in evaluating the balance of these benefits and risks. Histamine H2 receptor antagonists (H2-blockers), which are currently available only by prescription, are presented as a case study and were examined to determine how OTC availability of these agents would alter the patterns, effectiveness, and risks of self-treatment for acid-peptic disorders. Currently, about 5.7 million persons experience an episode of dyspepsia during any given quarter, of whom 3.5 million self-medicate with antacids. Study results indicate that OTC availability of H2-blockers would: 1) increase the proportion of persons with dyspepsia who self-medicate from 61.8% currently to 64.1%; 2) increase the proportion of persons who experience complete relief of their symptoms while self-medicating from 37.9% currently to 43.2%; 3) result in 14 additional cases of serious hematologic disorders and an additional 22,000 instances of minor side effects per quarter, but cause the overall rate of side effects among persons who self-medicate to decline; 4) cause an additional 300 persons per quarter with gastric cancer to self-medicate before seeking professional care, but cause no change in the median time between onset of symptoms and the decision to seek such care; and 5) decrease by 277,000 the number of persons per quarter who seek professional care for dyspepsia. On balance, results suggest that OTC H2-blockers may be a relatively safe and effective means of self-care for acid-peptic disorders, and may substantially reduce the number of patient encounters with the medical care system for minor gastrointestinal complaints. This study also illustrates the potential utility of the techniques of decision analysis to the formulation of drug regulatory policy.

Aged↗

PubMed1990

Menopause and heart disease. A review.

A large number of studies of disparate design are reasonably consistent in demonstrating that women with early bilateral oophorectomy are at increased risk of coronary heart disease. The evidence for an increase in risk among women with a surgical menopause but without bilateral oophorectomy is inconclusive, but such an effect, if any, could plausibly be explained by decreased ovarian function in many of those women as a consequence of the surgery. These findings, taken together with the lack of excess risk in women with bilateral oophorectomy who take replacement estrogen, support the view that the increased risk is due to estrogen deficiency. This view is further supported by the improvement in the lipid profile induced by estrogen replacement therapy in postmenopausal women. Because ovarian function begins to decline well before menopause, and continues to decline after menopause, it is not surprising that the moment of menopause is not associated with an abrupt increase in risk of heart disease. Moreover, some time is required for the adverse changes in coronary risk factors that occur during the climacteric to be reflected in increased rates of coronary disease. Although natural menopause does not cause an immediate increase in risk of heart disease, it does signal a period of increasing risk that is probably related both to age and to estrogen deficiency.

Adult↗

PubMed1990

The epidemiology of oral contraceptives and breast cancer.

Concern about a possible link with risk of breast cancer and use of oral contraceptives was raised soon after oral contraceptives were approved for general use. Over 35 epidemiologic studies have addressed this issue, but the controversy persists stimulated in particular by several recent studies. Overall, most studies have observed no consistent association between oral contraceptive use and risk of breast cancer. Nevertheless, the possibility remains that the risk may be elevated in certain subgroups, especially users of relatively long duration prior to their first full-term pregnancy. Most of the data regarding this subgroup derives from case-control studies, in which selection and recall bias may occur. To address this issue prospectively, our research group has established a new cohort of female nurses in the United States, aged 25-42. Enrollment is now complete, over 116,000 participants have returned the baseline questionnaire. A large proportion of these women are current or past oral contraceptive users. Within the next several years, substantial data will accrue to assess the relation between use of oral contraceptives at younger ages and risk of breast cancer.

Adult↗

PubMed1989

Prospective study of relative weight, height, and risk of breast cancer.

We examined relative weight and height in relation to subsequent breast cancer risk among 115,534 women 30 to 55 years of age and free from cancer in 1976. By 1984, six hundred fifty-eight premenopausal and 420 postmenopausal breast cancers were documented during 734,716 person-years. Among premenopausal women, risk of breast cancer decreased significantly with increasing relative weight (relative risk for the highest category was 0.6). A similar inverse association was seen for recalled relative weight at 18 years of age. Postmenopausal breast cancer was not associated with relative weight, either recent or at age 18. Height was not associated with breast cancer risk among premenopausal women and only weakly related among postmenopausal women. These data suggest that obesity among premenopausal and early postmenopausal women does not increase breast cancer risk substantially.

Adult↗

PubMed1989

The economic costs of non-insulin-dependent diabetes mellitus.

Persons with diabetes experience elevated risks of a variety of other illnesses-- including circulatory, visual, neurological, renal, and skin disorders--relative to their nondiabetic peers. Previous estimates of the economic burden of diabetes, however, have not taken full account of this related morbidity and mortality and have therefore understated the cost to the nation due to this disease. Accordingly, we estimated the economic costs of type II, or non-insulin-dependent, diabetes mellitus, reflecting its contribution to the total burden of disease in the United States. In 1986, non-insulin-dependent diabetes mellitus was responsible for $11.6 billion in health care expenditures, including $6.8 billion for diabetic care and $4.8 billion attributable to an excess prevalence of related (principally cardiovascular) conditions. The human toll of non-insulin-dependent diabetes mellitus included 144,000 deaths -- about 6.8% of total US mortality -- and the total disability of 951,000 persons. The total economic burden of non-insulin-dependent diabetes mellitus in 1986, including health care expenditures and productivity forgone due to disability and premature mortality, was $19.8 billion.

Aged↗

PubMed1989

Prospective study of smoking and the risk of breast cancer.

In 1976, 117,557 women in the United States aged 30-55 years and without a history of cancer provided detailed information on current smoking habits. By 1986, 1,788 cases of breast cancer had been documented during 1,133,682 person-years. There was no association between current smoking and risk of breast cancer (multivariate-adjusted relative risk for smokers of greater than or equal to 25 cigarettes/day compared to nonsmokers: 1.02, 95% confidence interval, 0.96-1.22). Past smoking also was unrelated to breast cancer risk (relative risk, 1.08; 95% confidence interval, 0.96-1.20). The results did not differ by menopausal status. Tumor size and the presence of nodal metastases were unrelated to smoking. Smoking was weakly associated with estrogen receptor-positive tumors (relative risk for smokers of greater than or equal to 25 cigarettes/day compared with never smokers, 1.38; 95% confidence interval, 1.04-1.84), but there was no dose-response relationship across categories of current smoking. These results suggest that smoking and breast cancer are not materially related.

Adult↗

PubMed1989

Prospective study of oral contraceptive use and risk of breast cancer in women.

In 1976, 118,273 female nurses 30-55 years of age with no history of cancer completed a questionnaire regarding possible risk factors. By 1986, after 1,137,415 person-years of follow-up, we had documented 1,799 newly diagnosed cases of breast cancer. Compared with the risk of breast cancer for nonusers of oral contraceptives, the multivariate relative risks were 1.07 (95% confidence interval, 0.97-1.19) for all users, 1.06 (95% confidence interval, 0.96-1.18) for past users, and 1.53 (95% confidence interval, 1.06-2.19) for current users--women who used oral contraceptives up to 2 years before diagnosis of breast cancer. We conclude that overall past use of oral contraceptives is not associated with a substantial increase in the risk of breast cancer. Although we did not find women who used oral contraceptives before the first pregnancy to have an increased risk of breast cancer, the number of women who used oral contraceptives for a long duration in early reproductive life was too small to permit firm conclusions regarding the risk in this subgroup.

Adult↗