Biomedical subjects

G A Colditz

Publications and source records attributed to G A Colditz.

At least 379 records · Page 21Linked to original sources

PubMed1993

Smoking cessation and decreased risk of stroke in women.

OBJECTIVE: To prospectively examine the relationship of time since stopping smoking with risk of stroke in middle-aged women. DESIGN: An ongoing prospective cohort of women with 12 years' follow-up data (1976 to 1988), in which information on smoking habits was updated every 2 years by postal questionnaire. POPULATION STUDIED: A total of 117,006 female registered nurses aged 30 to 55 years in 1976 and free of coronary heart disease, stroke, and cancer at baseline. MAIN OUTCOME MEASURES: Incident strokes (fatal and nonfatal), further subdivided into ischemic stroke, subarachnoid hemorrhage, and cerebral hemorrhage. RESULTS: The age-adjusted relative risk of total stroke among current smokers compared with never smokers was 2.58 (95% confidence interval, 2.08 to 3.19). The corresponding relative risk among former smokers was 1.34 (95% confidence interval, 1.04 to 1.73). For total and ischemic stroke, the excess risks among former smokers largely disappeared from 2 to 4 years after cessation. The same patterns of decline were observed regardless of number of cigarettes smoked, the age at starting, or the presence of other risk factors for stroke. CONCLUSIONS: The risk of suffering among cigarette smokers declines soon after cessation and the benefits are independent of the age at starting and the number of cigarettes smoked per day.

Adult↗

PubMed1993

A prospective study of aspirin use and cataract extraction in women.

We examined the association between aspirin use and the rates of cataract extraction during 8 years of follow-up in a large prospective study of women, the Nurses' Health Study. From 1980 to 1988, we documented 448 senile cataracts diagnosed and extracted during 434,680 person-years of follow-up. While we observed a modest positive association at the higher doses of aspirin use in the age-adjusted analyses, no association was found after accounting for other cataract risk factors (relative risk for > or = 20 years of use, 1.08; 95% confidence interval, 0.84 to 1.39). Among women who consumed seven or more tablets per week for 20 or more years, there was no suggestion of protection; if anything, a nonsignificantly elevated risk was observed (relative risk, 1.31; 95% confidence interval, 0.94 to 1.80). We observed no consistent difference in the relationship between aspirin use and cataract when assessed by age. Overall, we found no evidence to support the substantial reduction in risk of cataract among aspirin users as reported in several previous studies.

Age Factors↗

PubMed1993

Recall and selection bias in reporting past alcohol consumption among breast cancer cases.

Recall and selection bias are well-recognized potential problems in case-control studies of alcohol and cancer, but few analyses have attempted to assess the direction and the magnitude of these potential biases. We thus examined alcohol consumption in relation to risk of breast cancer using dietary questionnaires administered both before and after the diagnosis of breast cancer in the Nurses' Health Study (United States). Among cohort members who completed a dietary questionnaire in 1986 and who were free of cancer, 616 were diagnosed with breast cancer during follow-up to December 1989. These cases and 1,277 controls (a random sample of cohort members who did not develop cancer up to 1990) then were sent another questionnaire inquiring about their diet in 1985. Four hundred and ninety-four cases (80.2 percent) and 999 controls (78.2 percent) responded to the second questionnaire. The analysis based on the prospective (1986) questionnaire demonstrated an elevated risk of breast cancer among women who drank 30 or more g of alcohol daily (about two drinks) relative to nondrinkers (odds ratio [OR] = 1.55, 95 percent confidence interval [CI] = 1.01-2.39). The analysis based on the retrospective questionnaire also indicated a similar but slightly attenuated elevation of risk of breast cancer among women who drank at least 30 g daily (OR = 1.42, CI = 0.85-2.40). In these data, bias due to selection and recall had only minor effects on reported intake of alcohol consumption.

Adult↗

PubMed1993

Reproducibility and validity of food intake measurements from a semiquantitative food frequency questionnaire.

Few food frequency questionnaires have been evaluated for their ability to assess intakes of individual foods that may be related to disease independently of their nutrient content. The reproducibility and validity of food intake measurements by a 131-item semiquantitative food frequency questionnaire were evaluated in a sample of 127 men from the Health Professionals Follow-up Study, a large longitudinal study of diet and disease. Each subject completed two questionnaires 1 year apart and two 1-week diet records 6 months apart during the intervening year. Pearson correlations assessing reproducibility between food intakes from the two questionnaires ranged from .31 for pie to .92 for coffee (mean = .59). Validity was measured by comparing food intakes from the second questionnaire with those from the diet records. Pearson correlations corrected for within-person weekly variation in diet record data ranged from .17 for other nuts to .95 for bananas (mean = .63). Large within-person variation precluded the calculation of accurate validity correlations for 29 foods. As we previously observed in women, the foods most often overreported were fruits and vegetables, and meats and dairy products were most often underreported. With few exceptions, reasonable levels of reproducibility and validity were observed for intake of individual foods in this extensive food frequency questionnaire.

Adult↗

PubMed1993

A meta-analysis of cholecystectomy and risk of colorectal cancer.

BACKGROUND: Over 60 studies have addressed the hypothesis that the risk of colorectal cancer is increased following cholecystectomy; these studies have yielded inconsistent findings. The aim of the present study was to quantitatively summarize the results from the collective studies. METHODS: A meta-analysis of the published studies addressing the relation between cholecystectomy and colorectal cancer was conducted. RESULTS: The combined results from 33 case-control studies showed an association between cholecystectomy and risk of colorectal cancer (pooled relative risk [RR] = 1.34; 95% confidence interval [CI] = 1.14-1.57), particularly when limited to the proximal colon (RR = 1.88; 95% CI = 1.54-2.30). In most studies, the risk was stronger when the first 5-15 years following the surgery were excluded. The results from 6 cohort studies, with follow-up to approximately 15 years postcholecystectomy, were generally null (RR = 0.97; 95% CI = 0.82-1.14). A more limited body of evidence suggests that cholelithiasis is related to an elevated risk of proximal colon cancer. CONCLUSIONS: Because the risks varied substantially by study design and because time since cholecystectomy or potentially confounding factors were often not considered, we could not firmly quantitate this risk. However, the findings are consistent with other evidence that suggests some characteristic of bile acid metabolism increases the risk of cancer of the proximal colon.

Case-Control Studies↗

PubMed1993

Hormone replacement therapy and risk of breast cancer: results from epidemiologic studies.

OBJECTIVE: We combined data from published reports of the relation between estrogen use and breast cancer. We specifically addressed the hypothesis that the addition of progestins to estrogen therapy reduces the risk of breast cancer. STUDY DESIGN: A meta-analysis was performed. RESULTS: Replacement hormone therapy is not associated with increased risk of breast cancer in women who have ever used it (relative risk 1.02, 95% confidence interval 0.93 to 1.12). However, current use is associated with increased risk (relative risk 1.40, 95% confidence interval 1.20 to 1.63). Although there was no significant trend with increasing duration of use, women with > or = 10 years of estrogen use had a relative risk of 1.23 (95% confidence interval 1.08 to 1.40). However, data on use of estrogen plus progestins combined from four studies indicate that risk is not reduced and that the overall relative risk is 1.13 (95% confidence interval 0.78 to 1.64). Further, risk did not vary in strata of family history or benign breast disease. CONCLUSION: Although these results exclude a large effect of hormone therapy on risk of breast cancer, we are unable to rule out some risk associated with current or long-term estrogen use.

Breast Neoplasms↗

PubMed1993

The relationship of caloric intake to frequency of dieting among preadolescent and adolescent girls.

OBJECTIVE: To assess the relationships of concern with weight and shape, frequency of dieting, body mass index (weight/height2), and energy intake among 431 preadolescent and adolescent girls from a working-class New England suburb. METHOD: A cross-sectional study design used self-report measures of concern with weight, frequency of dieting, and average dietary intake. RESULTS: Approximately 30% of the girls in each age stratum were above the national age-standardized 85th percentile for body mass index (BMI). Body mass index was positively associated with concern about weight and shape (r = 0.46, p = 0.0001) and frequency of dieting (r = 0.49, p = 0.0001). Extreme concern with weight and shape was most common among the obese preadolescent and adolescent girls; however, dissatisfaction was also present among the underweight females. Fifty percent of the girls who were below the national age-standardized 15th percentile for BMI reported their ideal weight is less than their current weight, implying that among young women thinness is not adequate protection against dissatisfaction with weight and shape. Frequency of dieting was positively associated with concern about weight and shape (r = 0.53, p = 0.001) but not physical activity (r = -0.04, p = 0.36). Overall, we did not find strong evidence that dieters were eating less than their nondieting peers. Only among high school students was there a significant negative association between frequency of dieting and energy intake (r = -0.20, p = 0.01), suggesting that "dieting" may have a different meaning to preadolescents and adults. CONCLUSIONS: These findings indicate that self-reported frequent dieting in preadolescent and young adolescent girls is more indicative of extreme concern with weight than of decreased energy intake. Furthermore, extreme concern with weight and shape is most common among the obese preadolescent and adolescent girls.

Adolescent↗

PubMed1993

Activity, inactivity, and obesity: racial, ethnic, and age differences among schoolgirls.

Physical activity, inactivity, and obesity were assessed by questionnaire among a multiethnic sample of 552 girls in grades 5 through 12. Hispanics and Asians reported lower activity levels than other racial groups. Only 36% of the entire sample and less than one fifth of either Asians or Hispanics met the year 2000 goal for strenuous physical activity. Physical activity was inversely associated with age and age-adjusted body mass index. Obesity was unrelated to inactivity.

Adolescent↗

PubMed1993

Cigarette smoking and the risk of diabetes in women.

OBJECTIVES: Noninsulin-dependent diabetes mellitus, a major risk factor for cardiovascular disease, is prevalent in more than 12 million Americans. A voluminous amount of data demonstrates that cigarette smoking is an important cause of cancer and coronary heart disease. However, the association between cigarette smoking and the risk of diabetes is virtually unexplored, especially in women. METHODS: We examined the association between smoking and the incidence of noninsulin-dependent diabetes mellitus among 114,247 female nurses who were free of diabetes, cardiovascular disease, and cancer in 1976. We collected exposure information and disease status prospectively for 12 years from biennially self-administered questionnaires. RESULTS: Current smokers had an increased risk of diabetes, and we observed a significant dose-response trend for higher risk among heavier smokers. During 1,277,589 person-years of follow-up, 2333 women were clinically diagnosed with diabetes. The relative risk of diabetes, adjusted for obesity and other risk factors, was 1.42 among women who smoked 25 or more cigarettes per day compared with nonsmokers. CONCLUSIONS: These data suggest that cigarette smoking may be an independent, modifiable risk factor for noninsulin-dependent diabetes mellitus.

Adult↗

PubMed1993

Smoking and suicide among nurses.

Current evidence suggests a strong positive correlation between cigarette consumption and depression; this study examined the relationship between cigarettes and suicide. Over 100,000 predominantly White, middle-aged, female registered nurses were followed via biannual questionnaires from 1976 through 1988. Respondents smoking 1 through 24 cigarettes per day had twice the risk and those smoking 25 or more cigarettes four times the risk of committing suicide, compared with those who had never smoked. Although no information on causation was available, this paper links cigarettes to another major health problem.

Adult↗

PubMed1993

Comparison of diets of diabetic and nondiabetic women.

OBJECTIVE: To assess the dietary habits of diabetic women. RESEARCH DESIGN AND METHODS: Participants in the Nurses Health Study, a cohort of 121,700 registered female nurses, were followed since 1976. We compared the usual dietary intakes of women who had been diagnosed with diabetes mellitus by 1980 and age-matched nondiabetic control women; diets of these women were assessed in 1980 and 1984 by a semiquantitative food frequency questionnaire. The study examined 162 IDDM women and 738 NIDDM women. Similar comparisons were made for 429 women who developed NIDDM between 1980 and 1984. RESULTS: Although differences were small, women with IDDM in 1984 and women with NIDDM in 1980 and 1984 consumed less energy from carbohydrates, especially from sucrose, and more energy from protein and fat than did control women. Similar results were also found in 1984 for the 429 women who developed NIDDM between 1980 and 1984. In 1980, energy from nonsucrose carbohydrate was slightly higher in both IDDM and NIDDM women than in the control women. However, in 1984, using a dietary questionnaire designed to assess more complete dietary intake, less consistent results were obtained. Diabetic women tended to avoid desserts and sweets, sugar-containing beverages, and alcoholic beverages but consumed more meat and meat products. Intakes of foods high in complex carbohydrates (e.g., bread, rice, pasta, and potatoes) were similar between diabetic and control women. CONCLUSIONS: The results suggest that these diabetic women did not consume the high-carbohydrate, low-fat diets that the American Diabetes Association has been recommending over the past decade.

Adult↗

PubMed1992

A prospective study of cigarette smoking and risk of cataract surgery in women.

OBJECTIVE: To examine prospectively the association between cigarette smoking and the risk of cataract extraction in women. DESIGN: Prospective cohort study beginning in 1980 with 8 years of follow-up. SETTING: United States, multistate. PARTICIPANTS: Registered nurses 45 to 67 years of age and free of diagnosed cancer. There were 50,828 women included in 1980 and others were added as they became 45 years of age. MAIN OUTCOME MEASURE: Incidence of senile cataract extraction. RESULTS: We documented 493 incident senile cataracts diagnosed and extracted during 470,302 person-years of follow-up. The age-adjusted relative risk (RR) among women who smoked at least 65 pack-years was 1.63 (95% confidence interval [Cl], 1.18 to 2.26; P for trend, .02). A similar increase in RR was noted when smoking was assessed in terms of number of cigarettes currently smoked or number of cigarettes smoked by past smokers. Results were also similar after adjusting for other potential risk factors for cataract. Smoking was also strongly associated with posterior subcapsular cataract specifically (RR, 2.59; 95% Cl, 1.49 to 4.50 for greater than or equal to 65-pack-year smokers relative to nonsmokers. CONCLUSION: Smoking appears to increase the risk of cataract extraction.

Aged↗

PubMed1992

Nutrient intake and cataract extraction in women: a prospective study.

OBJECTIVE: To examine prospectively the association between dietary intake of vitamins C and E, carotene, and riboflavin and cataract extraction in women. DESIGN: Prospective cohort study beginning in 1980 with eight years of follow up. SETTING: 11 states of the United States. PARTICIPANTS: Female registered nurses who were 45 to 67 years of age. 50,828 women were included in 1980 and others were added as they became 45 years of age. MAIN OUTCOME MEASURE: Incidence of extraction of senile cataracts. RESULTS: 493 cataracts were extracted during 470,302 person years of follow up. Intake of carotene and vitamin A was inversely associated with cataract: in multivariate analyses, women in the highest fifth of total vitamin A intake (excluding supplements) had a 39% lower risk of cataract relative to women in the lowest fifth (relative risk 0.61; 95% confidence interval 0.45 to 0.81). Neither riboflavin nor dietary vitamins E or C were associated with cataract in a multivariate analysis. Among specific food items spinach (rather than carrots, the greatest source of beta carotene) was most consistently associated with a lower relative risk. The risk of cataract was 45% lower among women who used vitamin C supplements for 10 or more years(relative risk 0.55 (0.32 to 0.96)), but no association was noted for multivitamin intake. CONCLUSION: Dietary carotenoids, although not necessarily beta carotene, and long term vitamin C supplementation may decrease the risk of cataracts severe enough to require extraction.

Aged↗

PubMed1992

A long-term study of mortality in men who have undergone vasectomy.

BACKGROUND: Vasectomy is a reliable and widely accepted method of contraception, but there is some uncertainty and few data about a possible long-term adverse effect on health. METHODS: We examined the relation between vasectomy and mortality rates from cardiovascular disease, cancer, and all causes in a retrospective cohort of husbands of members of the Nurses' Health Study. In 1989 we obtained data by questionnaire on 14,607 men who had undergone vasectomy as of 1976 and 14,607 men who had not. RESULTS: Among the men who were free of cancer at the start of the study, 1052 died: 446 of cardiovascular disease, 341 of cancer, and 265 of other causes. Vasectomy was associated with reductions in mortality from all causes (age-adjusted relative risk, 0.85; 95 percent confidence interval, 0.76 to 0.96) and mortality from cardiovascular disease (relative risk, 0.76; 95 percent confidence interval, 0.63 to 0.92). Vasectomy was unrelated to mortality from all forms of cancer (relative risk, 1.01; 95 percent confidence interval, 0.82 to 1.25). Among men who had a vasectomy at least 20 years earlier, the procedure had no relation to mortality from all causes (relative risk, 1.11; 95 percent confidence interval, 0.92 to 1.33) or that from cardiovascular disease (relative risk, 0.85; 95 percent confidence interval, 0.63 to 1.16). However, mortality from cancer was increased in men who had a vasectomy at least 20 years earlier (relative risk, 1.44; 95 percent confidence interval, 1.07 to 1.92). The excess risk of cancer in these men was due primarily to lung cancer. None of the observed associations were confounded by smoking habits, body-mass index, alcohol consumption, or educational level. CONCLUSIONS: Vasectomy is not associated with an increase in overall mortality or mortality from cardiovascular disease. Our study also found no increase in overall mortality from cancer after vasectomy, but there was an apparent increase in the risk of cancer 20 or more years after vasectomy that requires further study.

Adult↗

PubMed1992

Reproducibility and validity of an expanded self-administered semiquantitative food frequency questionnaire among male health professionals.

The authors assessed the reproducibility and validity of an expanded 131-item semiquantitative food frequency questionnaire used in a prospective study among 51,529 men. The form was administered by mail twice to a sample of 127 participants at a one-year interval. During this interval, men completed two one-week diet records spaced approximately 6 months apart. Mean values for intake of most nutrients assessed by the two methods were similar. Intraclass correlation coefficients for nutrient intakes assessed by questionnaires one year apart ranged from 0.47 for vitamin E without supplements to 0.80 for vitamin C with supplements. Correlation coefficients between the energy-adjusted nutrient intakes measured by diet records and the second questionnaire (which asked about diet during the year encompassing the diet records) ranged from 0.28 for iron without supplements to 0.86 for vitamin C with supplements (mean r = 0.59). These correlations were higher after adjusting for week-to-week variation in diet record intakes (mean r = 0.65). These data indicate that the expanded semiquantitative food frequency questionnaire is reproducible and provides a useful measure of intake for many nutrients over a one-year period.

Age Factors↗

PubMed1992

A prospective study of benign breast disease and the risk of breast cancer.

OBJECTIVE: To examine the relation between proliferative benign breast disease with and without atypical hyperplasia and the subsequent risk of breast cancer. DESIGN: Case-control study nested within a prospective cohort study. Median follow-up after breast biopsy was 8 years (25th to 75th percentile, 5 to 14 years). PARTICIPANTS: Selected from a prospective cohort of 121,700 US registered nurses followed up from 1976 to 1986. Cases were women with breast cancer who had a prior biopsy for benign breast disease. Controls were randomly selected and matched on year of biopsy and year of birth from among women in the cohort who had a benign breast biopsy but who did not develop breast cancer. Included in the analysis were 121 cases and 488 controls. MAIN OUTCOME MEASURE: Development of breast cancer. RESULTS: Slides from the first benign breast biopsy were reviewed by two breast pathologists blinded to the outcome. The multiply adjusted relative risks (RRs) for breast cancer, relative to women with no proliferative disease, were 1.6 for proliferative disease without atypia (95% confidence interval [Cl], 1.0 to 2.5) and 3.7 for atypical hyperplasia (95% Cl, 2.1 to 6.8). Breast cancer risk was more strongly associated with atypical hyperplasia among premenopausal women (RR = 5.9; 95% Cl, 2.9 to 13.2) than postmenopausal women (RR = 2.3; 95% Cl, 0.9 to 5.9), but the association of breast cancer risk with proliferative disease without atypia did not differ across menopausal status. CONCLUSION: These results confirm the marked increase in breast cancer risk among women with atypical hyperplasia, particularly in premenopausal women, and suggest that these women should be encouraged to undergo frequent breast cancer screening.

Breast↗

PubMed1992

Comparison of measures of fatty acid intake by subcutaneous fat aspirate, food frequency questionnaire, and diet records in a free-living population of US men.

In 1986-1987, the authors assessed the fatty acid intake of 118 Boston-area men, aged 40-75 years, by a semiquantitative food frequency questionnaire administered twice, by two 7-day diet records, and by capillary gas chromatography of subcutaneous fat samples obtained by needle aspirate from the lateral buttock. Spearman correlation coefficients between diet record estimates of fatty acid intake (as a percentage of total fat) and fat aspirate measures (as a percentage of total peak area) were as follows: saturated fat, r = 0.16 (p = 0.09); monounsaturated fat, r = 0.22 (p = 0.01); and polyunsaturated fat, r = 0.49 (p = 0.0001). Spearman correlation coefficients between estimates derived from the food frequency questionnaire were as follows: saturated fat, r = 0.18 ( p = 0.05); monounsaturated fat, r = 0.14 (p = 0.14); polyunsaturated fat, r = 0.50 (p = 0.0001); and eicosapentaenoic acid, r = 0.47 (p = 0.0001). These data confirm that the polyunsaturated and eicosapentaenoic fatty acid content of subcutaneous fat is a measure of dietary intake of these fats. Although diet records are commonly thought to be the "gold standard" method of dietary assessment, the similar correlations observed between the fatty acid composition of adipose tissue and estimates of intake from the food frequency questionnaire and from diet records suggest that these two dietary assessment methods have similar validity in the measurement of polyunsaturated fatty acid intake.

Adipose Tissue↗

PubMed1992

Cost-effectiveness and cost-benefit analyses in the medical literature. Are the methods being used correctly?

OBJECTIVE: To determine whether published cost-effectiveness and cost-benefit analyses have adhered to basic analytic principles. DESIGN: Structured methodologic review of published articles. STUDY SAMPLE: Seventy-seven articles published either from 1978 to 1980 or from 1985 to 1987 in general medical, general surgical, and medical subspecialty journals. MAIN OUTCOME MEASUREMENTS: Articles were reviewed to assess the use and reporting of six fundamental principles of analysis. These principles were derived by reviewing widely cited textbooks and articles describing the methods for performing economic analyses and by selecting the methods universally recommended. MAIN RESULTS: Overall performance was only fair. Three articles adhered to all six principles, and the median number of principles to which articles adhered was three. Among the problems noted were failure to make underlying assumptions explicit and, therefore, verifiable, and failure to test assumptions with sensitivity analyses. No improvement in performance was observed between 1978 and 1987. Articles in general medical journals, however, were more likely to use analytic methods appropriately than articles in the general surgical or medical subspecialty literature. CONCLUSIONS: Greater attention should be devoted to ensuring the appropriate use of analytic methods for economic analyses, and readers should make note of the methods used when interpreting the results of economic analyses.

Cost-Benefit Analysis↗