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Biomedical subjects

G A Colditz

Publications and source records attributed to G A Colditz.

At least 235 records · Page 13Linked to original sources
PubMed1997

Dietary fiber, glycemic load, and risk of non-insulin-dependent diabetes mellitus in women.

OBJECTIVE: To examine prospectively the relationship between glycemic diets, low fiber intake, and risk of non-insulin-dependent diabetes mellitus. DESIGN: Cohort study. SETTING: In 1986, a total of 65173 US women 40 to 65 years of age and free from diagnosed cardiovascular disease, cancer, and diabetes completed a detailed dietary questionnaire from which we calculated usual intake of total and specific sources of dietary fiber, dietary glycemic index, and glycemic load. MAIN OUTCOME MEASURE: Non-insulin-dependent diabetes mellitus. RESULTS: During 6 years of follow-up, 915 incident cases of diabetes were documented. The dietary glycemic index was positively associated with risk of diabetes after adjustment for age, body mass index, smoking, physical activity, family history of diabetes, alcohol and cereal fiber intake, and total energy intake. Comparing the highest with the lowest quintile, the relative risk (RR) of diabetes was 1.37 (95% confidence interval [CI], 1.09-1.71, P trend=.005). The glycemic load (an indicator of a global dietary insulin demand) was also positively associated with diabetes (RR= 1.47; 95% CI, 1.16-1.86, P trend=.003). Cereal fiber intake was inversely associated with risk of diabetes when comparing the extreme quintiles (RR=0.72, 95% CI, 0.58-0.90, P trend=.001). The combination of a high glycemic load and a low cereal fiber intake further increased the risk of diabetes (RR=2.50, 95% CI, 1.14-5.51) when compared with a low glycemic load and high cereal fiber intake. CONCLUSIONS: Our results support the hypothesis that diets with a high glycemic load and a low cereal fiber content increase risk of diabetes in women. Further, they suggest that grains should be consumed in a minimally refined form to reduce the incidence of diabetes.

Adult↗
PubMed1997

Past use of oral contraceptives and the risk of developing systemic lupus erythematosus.

OBJECTIVE: To examine the relationship between past use of oral contraceptives (OCs) and development of systemic lupus erythematosus (SLE). METHODS: Prospective cohort study of 121,645 women who were followed up every 2 years between 1976 and 1990 as part of the Nurses' Health Study. Women were classified as never users or past users of OCs based on self-report. Incidence of SLE was defined by 1) strict American College of Rheumatology (ACR) classification criteria (> or = 4 ACR criteria), 2) > or = 4 ACR criteria and any physician's diagnosis, 3) > or = 4 ACR criteria and diagnosis by an ACR-certified rheumatologist, 4) > or = 3 ACR criteria, or 5) diagnosis by a physician even if the patient did not meet the ACR criteria. RESULTS: Compared with never users of OCs, and after adjusting for age and ever use of postmenopausal hormones, the relative risk (95% confidence interval [95% CI]) for the incidence of SLE in the women who had definite cases of SLE (> or = 4 ACR criteria) (n = 99) was 1.4 (0.9-2.1) for past users of OCs. Using the most stringent case definition (ACR criteria plus a diagnosis of SLE by an ACR member) (n = 58), the relative risk for past users compared with never users was 1.9 (95% CI 1.1-3.3). No relationship was observed between duration of OC use or time since first use and the risk of developing SLE. CONCLUSION: Past use of OCs was associated with a slightly increased risk of developing SLE. The decision to use hormonal contraception must be individualized, but the small absolute risk observed for the development of SLE in white women should not be a dominant factor in the decision.

Cohort Studies↗
PubMed1997

Racial/ethnic and gender differences in concern with weight and in bulimic behaviors among adolescents.

This study examined cross-sectional gender and racial/ ethnic differences in bulimic behaviors among adolescents. Subjects were 704 male and 621 female students at a large urban public high school in the Northeast. Approximately 61% of the girls and 43% of the boys reported trying to lose weight or maintain their current weight; 2.0% of the students reported using laxatives or vomiting to control their weight. The use of these behaviors to control weight was only slightly more common among girls than boys (2.7% vs. 1.4%, p = 0.1). Although more black than white girls used laxatives or vomiting to control weight (odds ratio [OR] = 11.9, 95% confidence interval [CI] 1.5-95.3), there were no racial/ethnic differences in these behaviors among boys. However, Hispanic boys were twice as likely as white boys to binge eat at least monthly (OR = 2.0, 95% CI 1.1-3.6). Our results suggest that bulimic behaviors affect male and female adolescents from a variety of racial/ethnic backgrounds. In addition, in contrast to the large gender differences in the prevalence of dieting and binge eating, more modest differences were documented in the prevalence of using vomiting and laxatives to control weight.

Adolescent↗
PubMed1997

A prospective study of thiazide use and fractures in women.

Thiazide diuretics reduce urinary calcium and may inhibit bone resorption, and hence may help to attenuate age-related bone loss and to lower the risk of osteoporotic fracture. We followed 83728 women, who were 36-61 years of age at baseline in 1982, for 10 years with biennial mailed questionnaires on which they reported incident fractures, use of thiazide diuretics, and other medical behavioral information. From descriptions of fracture sites and circumstances, 251 hip (proximal femur) and 1594 forearm (distal radius) fractures were identified as low or moderate trauma events. After controlling for age, body mass index, menopausal status, postmenopausal hormone use, cigarette smoking and dietary factors, we observed a statistically significant 22% reduction in the risk of forearm fractures among current thiazide users compared with women who reported no thiazide use. Risk appeared to decline with longer duration of use, reaching a 37% reduction in risk among women who had been using thiazides for 8 or more years. For hip fractures, thiazide use was protective among the postmenopausal women (relative risk = 0.69, 95% confidence interval 0.48-0.99). We conclude that the potential benefit of thiazide diuretics for osteoporosis should be considered when prescribing antihypertensive treatment.

Adult↗
PubMed1997

Reproducibility of oral contraceptive histories and validity of hormone composition reported in a cohort of US women.

Histories of oral contraceptive (OC) use were reported by 116,686 women aged 25 to 42 years in the Nurses' Health Study II on a self-administered questionnaire accompanied by a color photo booklet of all OC preparations ever marketed in the US. To evaluate the quality of this information, we compared the responses of a randomly selected sample of 215 participants with their data from a subsequent, detailed telephone interview using a structured life events calendar. Agreement for a history of ever having used OC was high between the two methods (exact agreement 99%). Reported durations of use were equivalent (mean duration 42.7 months by telephone interview and 44.6 months by questionnaire). The Spearman correlation for duration of use calculated from the two methods was 0.94 (p < 0.0001). For a subset of women for whom we were able to obtain OC prescription records, the medical record confirmed the use of an identical or equivalent brand in 75% of intervals of reported use. Acceptably valid OC histories were obtained with a self-administered questionnaire.

Adult↗
PubMed1997

Variation in the incidence of uterine leiomyoma among premenopausal women by age and race.

OBJECTIVE: To quantify the incidence of uterine leiomyoma confirmed by hysterectomy, ultrasound, or pelvic examination according to age and race among premenopausal women. METHODS: From September 1989 through May 1993, 95,061 premenopausal nurses age 25-44 with intact uteri and no history of uterine leiomyoma were followed to determine incidence rates of uterine leiomyoma. The self-reported diagnosis was confirmed in 93% of the medical records obtained for a sample of cases. Using pooled logistic regression, we estimated relative risks (RRs) of uterine leiomyoma according to race and examined whether adjustment for other potential risk factors could explain the variation in the race-specific rates. RESULTS: During 327,065 woman-years, 4181 new cases of uterine leiomyoma were reported. The incidence rates increased with age, and the age-standardized rates of ultrasound- or hysterectomy-confirmed diagnoses per 1000 woman-years were 8.9 among white women and 30.6 among black women. After further adjustment for marital status, body mass index, age at first birth, years since last birth, history of infertility, age at first oral contraceptive use, and current alcohol consumption, the rates among black women were significantly greater for diagnoses confirmed by ultrasound or hysterectomy (RR 3.25; 95% confidence interval [CI] 2.71, 3.88) and by hysterectomy (RR 1.82; 95% CI 1.17, 2.82) compared with rates among white women. We observed similar RRs when the cohort was restricted to participants who reported undergoing a screening physical examination within the 2 years before baseline. CONCLUSION: A higher prevalence of known risk factors did not explain the excess rate of uterine leiomyoma among premenopausal black women.

Adult↗
PubMed1997

Distinguishing recovery from remission in a cohort of bulimic women: how should asymptomatic periods be described?

BACKGROUND: Empirical definitions of remission and recovery from eating disorders are needed to understand outcome data and compare results across studies. METHOD: 106 treatment-seeking women with bulimia nervosa, who had abstained from binging and purging for at least 4 weeks, were followed prospectively. Relapse was defined as at least 4 consecutive weeks of either binging and purging weekly or binging two or more times per week, regardless of purging. Recovery was differentiated from remission based on the probability of relapse. The minimum number of weeks after which the risk of relapse leveled off was used as the cut-off to distinguish between the two outcomes. Kaplan-Meier methods were used to estimate the weekly probability of relapse. RESULTS: When defining remission as at least 4 weeks of being asymptomatic, a quarter of the women relapsed within 11 weeks. By 37 weeks, only 49% of the women remained asymptomatic (95% CI, 41-61). The probability of relapse was substantial for approximately a year after a woman ceased to binge and purge. CONCLUSION: Bulimia nervosa is an episodic disorder. As a conservative approach, periods of being asymptomatic that last less than 1 year should be labeled as remissions, not recoveries.

Bulimia↗
PubMed1997

Parity and other reproductive factors and risk of adenomatous polyps of the distal colorectum (United States).

Evidence for an effect of reproductive factors on colorectal carcinogenesis is inconsistent and little is known about their role in development of precursor adenomatous polyps. We evaluated the relation between reproductive factors and distal colorectal adenomas (n = 982) during 14 years of follow up of 26,983 participants in the Nurses' Health Study (United States). The women were free of diagnosed cancer or polyps in 1980, underwent endoscopy 1980-94, and had reported on their parity, oral contraceptive (OC) use, and ages at menarche, first term-pregnancy, and menopause. We calculated relative risks (RR) and 95 percent confidence intervals (CI) using multiple logistic regression. Women with higher parity had an increased risk of adenomas of the distal colorectum (P trend = 0.004; 6+ cf 0 parity: RR = 1.3, CI = 0.9-1.8) or distal colon (P trend = 0.002, RR = 1.7, CI = 1.2-2.6). This association was significantly stronger among women with a family history of colorectal cancer (P interaction = 0.03); comparing 6+ term-pregnancies with nulliparity, among those with a family history, the RR for distal colon adenoma was 3.2 (CI = 1.4-7.2), while among those without a family history, the RR was 1.3 (CI = 0.8-2.2). We observed no association for distal colorectal adenoma and age at menarche, age at first term-pregnancy, ever use of OCs, or menopausal status. Further work is needed to clarify the relation of parity with colon adenoma risk.

Adenoma↗
PubMed1997

A prospective study of oral contraceptive use and risk of breast cancer (Nurses' Health Study, United States).

Results of previous epidemiologic studies have provided reassurance that there is little, if any, increase in risk of breast cancer with oral contraceptive (OC) use in general. However, in several studies, an increased risk of breast cancer has been observed in two subgroups, young women who used OCs for extended durations and in women who used OCs prior to a first-term pregnancy. We evaluated these relationships using data from the ongoing Nurses' Health Study cohort (United States). We documented 3,383 cases of breast cancer from 1976 to 1992 among 1.6 million person-years of follow-up. We observed no overall relationship between duration of OC use and breast cancer risk, even among women who reported using OCs for 10 or more years (multivariate relative risk [RR] = 1.11, 95 percent confidence interval [CI] = 0.94-1.32). Among women less than 45 years of age, the multivariate RR for using OCs for 10 or more years was 1.07 (CI = 0.70-1.65) compared with never-users. The risk associated with five or more years of OC use prior to a first full-term pregnancy compared with never-use was 0.96 (CI = 0.65-1.43). Among women less than 45 years of age, we observed no evidence of an increased risk with OC use before a first full-term pregnancy (use for five or more years: RR = 0.57, CI = 0.24-1.31). Because of the age distribution of our cohort, we were unable to evaluate these relationships among women less than 40 years of age. Our study provides considerable evidence that long-term past OC use, either overall or prior to a first full-term pregnancy, does not result in any appreciable increase in breast cancer risk in women over 40 years of age.

Adult↗
PubMed1997

Physical activity and reduced risk of colon cancer: implications for prevention.

This paper reviews the consistency of the relation between increased physical activity and reduced risk of colon cancer, estimates the potential prevention benefit from increasing population levels of physical activity, and considers social strategies to increase activity levels. The published literature was reviewed systematically and supplemented by MEDLINE searches through March 1997. Studies that reported a measure of physical activity and outcomes of colon cancer or colorectal cancer were included. We excluded the first report of a study that was expanded subsequently by extended follow-up, and any study that did not report the methods for measurement of physical activity. Data were extracted including details on study size, methods of classifying physical activity, and outcomes. A consistent inverse relation was observed such that increased physical activity was associated with reduced risk of colon cancer. About a 50 percent reduction in incidence was observed among those with the highest level of activity across numerous studies that used different measures of activity (occupational or leisure-time activity). This association persisted in studies using multivariate analyses to control for diet and other known or suspected risk factors for colon cancer. Risk reduction was attenuated in those studies that combined colon and rectal cancer. This review indicates that greater attention should be placed on social strategies to increase physical activity as a means of preventing colon cancer.

Colonic Neoplasms↗
PubMed1997

Skin cancer prevention: a time for action.

Skin cancer is the most common malignancy in the United States accounting for more than 840,000 cases and 9,400 deaths annually. It is estimated that 90% of non-melanoma skin cancers and much of melanoma incidence can be attributed to sun exposure. The evidence suggests that regular use of sunscreen (Sun Protective Factor (SPF) of 15 or higher), wearing protective, tightly woven clothing and wide brimmed hats, and avoiding sun exposure when the ultraviolet rays are strongest (between 11:00 a.m. and 3:00 p.m.) can dramatically reduce the risk of skin cancer. Interventions to promote sun-protection behaviors that target children and adults are necessary to reduce the growing incidence rate of skin cancer in the United States.

Adolescent↗
PubMed1997

Weight, weight gain, activity, and major illnesses: the Nurses' Health Study.

The Nurses' Health Study was initiated in 1976 to study the relation between oral contraceptives and breast cancer. Subsequent funding was available to follow the cohort to address relations between cigarette smoking, postmenopausal hormones, hair dyes, and a range of cancers including breast, endometrial, ovarian, and lung cancer. The 121,700 participating nurses are followed up every 2 years via mail questionnaire to update exposure information to identify incident cancers and other illnesses. Follow-up through 1994 has achieved 90% response from living cohort members. Over the course of the study, additional exposures have been added and refined, including weight at age 18, current weight, height, waist and hip measurements and history of major voluntary weight loss among others. Our focus has been on the health effects of weight gain during middle age. The results relating to diabetes, coronary heart disease, certain types of cancer and total mortality are reviewed. Our primary analytic tools have been multiple logistic regression and Cox proportional hazards models. These methods allow for flexibility in defining the exposures of interest as well as determining their relative importance while controlling for key risk factors. Our models show that even moderate weight gain after age 18 increases risk of each condition. The benefits of physical activity include reduced risk of disease. Issues in the measurement and validation of weight and activity highlight the complexities that are inherent in observational studies addressing the health consequences of lifestyles and anthropometric variables. Our experience of working with repeated measures of body weight and recreational activity are described. Recreational activity has been ascertained in various ways on several questionnaires and may be subject to misclassification. For both weight and activity it may be the pattern of these values that is of importance (e.g. "weight cycling") for some outcomes or conditions. Our research in this area is ongoing. These issues regarding longitudinal measurement will never be completely resolved because weight and activity are intrinsically complex concepts. For these and other such variables, the primary solution is to minimize the problems associated with longitudinal studies. This is best accomplished by developing and maintaining a very strong study design/protocol, including: careful consideration of the sample frame and sample size; maintenance of a high response rate; and continuous monitoring and improvement of the survey/interview instrument(s).

Activities of Daily Living↗
PubMed1997

The Nurses' Health Study: 20-year contribution to the understanding of health among women.

The Nurses' Health Study was designed as a prospective follow-up study to examine relations between contraception and breast cancer. With follow-up questionnaires mailed every 2 years, investigators have added extensive details of lifestyle practices. The study, currently in its 20th year, has maintained high follow-up with > 90% of participants responding to each of the follow-up cycles since 1988. The relations between use of hormones, diet, exercise, and other lifestyle practices have been related to the development of a wide range of chronic illnesses among women. This review describes the methods used to follow up the study participants and summarizes the major findings that have been described over the first 20 years of the study. We highlight additional areas added to the study in recent years to address emerging issues in women's health. Special emphasis is placed on the recent findings from the study, including relations between weight gain and heart disease, diabetes, and mortality, the lack of relation between calcium and osteoporotic fractures, and the positive relation between postmenopausal use of hormones and risk of breast cancer.

Adult↗
PubMed1997

Assessing diets of children and adolescents.

Because of the increased interest in the diets of children and adolescents and the possible relation between those diets and adulthood diseases, we reviewed nutritional assessment methods used specifically in young people. The assessment of diets of individual children and adolescents has evolved from Hasse's study of Swiss and Russian girls in 1882 to Burke's development of the dietary history to the Ten State Nutrition Survey. Currently, various government-sponsored surveys and several other assessment programs are studying the nutritional status of children and adolescents. We discuss the methods used in these investigations, compare the available dietary assessment tools (the dietary record, 24-h dietary recall, and food-frequency questionnaire), describe the development of a new food-frequency questionnaire (the Youth-Adolescent Questionnaire), and review new approaches. The data emerging from reproducibility studies suggest that food-frequency questionnaires provide enough accuracy in studies of adolescents to permit individual diets to be related to subsequent health outcomes.

Adolescent↗
PubMed1997

A prospective study of NAT2 acetylation genotype, cigarette smoking, and risk of breast cancer.

Polymorphisms in the N-acetyltransferase 2 (NAT2) gene are determinants of the rate of metabolic activation of carcinogenic compounds such as aryl aromatic amines. Homozygosity for any combination of three variant alleles in Caucasians defines 'slow' acetylators; presence of one or two wild-type alleles characterizes 'rapid' acetylators. Although most previous studies have not observed an overall elevation in risk of breast cancer among slow acetylators, a recent study observed that cigarette smoking was associated with a large increase in risk of breast cancer among slow acetylators. We assessed the relation between NAT2 acetylation status and breast cancer risk, and its interaction with smoking, in a prospective study of mainly Caucasian US women. Four hundred and sixty-six incident cases who were diagnosed with breast cancer after giving a blood specimen in 1989-90 were matched to 466 controls in a nested case-control study. NAT2 genotype was determined using PCR-RFLP assays. The multivariate relative risk (RR) comparing slow with rapid acetylators was 0.9 (95% CI 0.7-1.2). Among slow acetylators, current smoking immediately prior to diagnosis was not associated with a significant elevation in risk compared with never smoking rapid acetylators (RR = 1.4, 95% CI 0.7-2.6). No significant association was seen between pack-years of smoking and risk of breast cancer among either slow or fast acetylators. A non-significant elevation in risk was observed among women who smoked for > or = 5 years prior to first pregnancy and were rapid acetylators, compared with never smoking rapid acetylators (RR = 1.5, 95% CI 0.9-2.6). In analyses limited to 706 post-menopausal women, the elevated risks for current smokers immediately prior to diagnosis who were slow acetylators compared with never smokers who were fast acetylators were slightly stronger but still not statistically significant. In summary, we observed little evidence of an association between NAT2 genotype and breast cancer. In this prospective study, cigarette smoking was not appreciably associated with breast cancer among either slow or fast NAT2 acetylators.

Acetylation↗
PubMed1997

Calcium intake and the incidence of forearm and hip fractures among men.

High calcium intakes are thought to be associated with strong bones and lower risk of fractures. However, findings from epidemiologic studies have not been consistent. In addition, the vast majority of such studies were conducted among women, leading to a relative lack of data concerning men. The objective of this study therefore was to investigate the relation between adult calcium intake and risk of fractures among men in the Health Professionals Follow-up Study (HPFS). During 331,234 person-years of follow-up over an 8-y period, 201 forearm and 56 hip fractures due to low or moderate trauma were reported among 43,063 men 40-75 y of age in 1986 when they first completed a questionnaire about diet and lifestyle factors. After controlling for age, smoking status, body mass index (BMI), physical activity, alcohol consumption and total energy intake, the relative risk (RR) of forearm fractures for men in the highest quintile of calcium intake (from foods plus supplements) compared with those in the lowest quintile was 0.98 [95% confidence interval (CI) = 0.59-1.61; P for trend = 0.78]; for hip fractures, the comparable RR was 1.19 (95% CI = 0.42-3.35; P for trend = 0.58). Relative risks for consuming >2.5 glasses (600 mL) of milk per day compared with one (240 mL) or fewer per week were 1.06 (95% CI = 0.69-1.62; P for trend = 0.82) for forearm fractures and 0.97 (95% CI = 0.39-2.42; P for trend = 0.56) for hip fractures. In conclusion, these results do not support a relation between calcium intake and the incidence of forearm or hip fractures in men.

Adult↗
PubMed1997

Cancer incidence and mortality: the priority of screening frequency and population coverage.

In addition to the usual measures of screening-test performance, it is important to consider testing frequency when evaluating a screening program. Data on which to base recommendations for the timing of screening tests are urgently needed. For example, in the cases of cervical and colon cancer, when the target is a precursor lesion, research indicates that less frequent screening may be appropriate. This finding may not apply, however, to screening for breast cancer by mammography, which requires currently recommended intervals for the early detection of malignancies. Resources now allocated to breast cancer might more effectively be applied to the construction of tests that would permit longer intervals between screenings. To achieve the National Cancer Institute's goal of reducing cancer mortality in the United States by the year 2000, it will be important to review the balance between population coverage and individual screening for each cancer and to emphasize prevention strategies that maximize population coverage while minimizing expenditures.

Adult↗