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G Colditz

Publications and source records attributed to G Colditz.

At least 37 records · Page 2Linked to original sources
PubMed1998

Social networks, stress and health-related quality of life.

Although evidence suggests that social networks reduce the risk of mortality and are negatively associated with severe mental disability, little is known about their relationship to everyday functioning and health-related quality of life (HRQoL). In addition, the importance of social networks in the presence of chronic stress remains unclear. We examined the association between social networks and aspects of mental functioning (mental health, vitality and role-emotional functioning) and the relationship between social networks and mental functioning in the presence of stressors. Multiple linear and logistic regression models were used to examine data in 47,912 middle-aged and older healthy women. The Medical Outcomes Study Shortform Health Survey measured dimensions of quality of life. We observed strong associations between levels of social networks and multivariate-adjusted quality of life scores, particularly in potentially high stress situations. Compared to the most socially integrated, women who were socially isolated had reductions in mental health and vitality scores of 6.5 and 7.4 points, respectively and a 60% increased risk of limitation in role-emotional functioning. Social networks are positively associated with mental functioning in women. This association is strongest for women reporting high levels of home and work stressors.

Adult↗
PubMed1998

Predictors of weight change in men: results from the Health Professionals Follow-up Study.

OBJECTIVE: Since the prevalence of adult obesity is increasing in the United States, we examined the effect of changing common habits (exercise, TV viewing, smoking and eating habits) on four year change in body weight. DESIGN: A prospective cohort study of US male health professionals with follow-up from 1988-1992. Participants were 19478 men aged 40-75 in 1986, who were free of cancer, coronary heart disease, stroke and diabetes. METHODS: Multiple regression was used to determine the association between four year change in body weight (from 1988-1992) and common habits, after adjusting for baseline age, hypertension and hypercholesterolemia. RESULTS: For middle aged men, vigorous activity was associated with weight reduction and TV/VCR viewing and eating between meals with weight gain. Quitting smoking and a history of voluntary weight loss prior to the study period were consistently related to weight increase. Recently being on a diet was more strongly associated with weight loss among older men. Over the four year follow-up period, middle-aged men who increased their exercise, decreased TV viewing and stopped eating between meals, lost an average weight of -1.4 kg (95% confidence interval (CI) -1.6 - -1.1 kg), compared to a weight gain of 1.4 kg among the overall population. The prevalence of obesity among middle-aged men was lowest among those who maintained a relatively high level of vigorous physical activity, compared to those who were relatively sedentary. CONCLUSION: These data suggest that improvement in the mix of health habits, particularly increasing vigorous activity, as well as decreasing TV use and changing eating habits, results in weight maintenance or a modest weight loss over four years.

Adult↗
PubMed1998

Intention to have a mammogram in the future among women who have underused mammography in the past.

This study investigated associations between confidence in one's ability to discuss mammography with health providers and to obtain regular mammograms (self-efficacy), social network members' attitudes toward mammograms (social influence), mammography experiences, and intention to have a mammogram in the next 1 to 2 years among women who were not in adherence with screening guidelines. Data were collected as part of a baseline assessment for a work site intervention study. Women 52 years and older completed a self-administered survey. Those not in compliance with screening guidelines (n = 194) were included in the analyses. Logistic regression revealed that self-efficacy and strong supportive social influences were significantly associated with mammography intention (odds ratio [OR] = 2.50, OR = 2.22, respectively), adjusting for prior mammography use. Findings suggest that interventions designed to promote mammography should build women's confidence in their ability to discuss mammography with health providers and to obtain regular mammograms. Intervention among social networks may also be an effective means of promoting mammography.

Adult↗
PubMed1998

Use of toenail fluoride levels as an indicator for the risk of hip and forearm fractures in women.

The relation between fluoride intake and risk of osteoporotic fractures remains unclear. The lack of individual measures of long-term fluoride intake has limited epidemiologic studies. We used toenail fluoride in this study as a measure of long-term intake to evaluate the relation between fluoride intake and subsequent risk of hip and distal forearm fractures. Between 1982 and 1984, we collected toenail clippings from 62,641 women in the Nurses' Health Study who were free from cancer, heart disease, stroke, and previous hip or forearm fracture. We identified fracture cases (53 proximal femur and 188 distal forearm) through subsequent biennial mailed questionnaires and matched controls to cases on year of birth. The odds ratio of hip fracture among women in the highest quartile of toenail fluoride [ > 5.50 parts per million (ppm)], compared with those in the lowest quartile (> 2.00 ppm), was 0.8 (95% confidence interval = 0.2-4.0), with adjustment for menopausal status, postmenopausal hormone use, caffeine intake, and alcohol consumption. The corresponding adjusted odds ratio for forearm fracture was 1.6 (95% confidence interval = 0.8-3.1). Further adjustment for body mass index, smoking status, and calcium and vitamin D intake did not alter these results.

Adult↗
PubMed1997

Effects of body fat on ventilatory function in children and adolescents: cross-sectional findings from a random population sample of school children.

Childhood obesity is associated with a range of adverse consequences, and the prevalence is increasing in developed nations. Most of the literature on obesity and ventilatory function in children concerns samples selected for gross obesity with relatively little detail available from random population samples. This report examines the effect of total body fat as a percentage of weight (TBF%) on ventilatory function in a nationally representative sample of 2,464 Australian school children aged 9, 12, and 15 years. Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were used as measures of ventilatory function. TBF% was estimated from skinfold thickness measurements. Ventilatory function was adjusted (for height and then for both height and weight) using linear regression on a logarithmic scale. Adjustment was performed within separate strata of age and gender. Analysis of covariance was used for hypothesis testing. Height-adjusted FVC and FEV1 values increased significantly with increasing weight within each age and gender group and for all subjects combined (P < 0.0001). The effect of TBF% independent of lean tissue was examined using FVC and FEV1 values adjusted for both height and weight, because body weight measures both lean and fat mass. Adjusted FVC and FEV1 values decreased significantly with increasing TBF% within each age and gender group and for all subjects combined (P < 0.0001). Ventilatory function decreased with increasing proportions of body fat. This is consistent with previous findings on lean tissue mass and ventilatory function. Although the magnitude of the effect was relatively small in clinical terms, from a public health perspective our findings indicate yet another adverse consequence of childhood obesity.

Adolescent↗
PubMed1994

Guidelines for meta-analyses evaluating diagnostic tests.

OBJECTIVES: To introduce guidelines for the conduct, reporting, and critical appraisal of meta-analyses evaluating diagnostic tests and to apply these guidelines to recently published meta-analyses of diagnostic tests. DATA SOURCES: Based on current concepts of how to assess diagnostic tests and conduct meta-analyses. They are applied to all meta-analyses evaluating diagnostic tests published in English-language journals from January 1990 through December 1991, identified through MEDLINE searching and by experts in the field. STUDY SELECTION: Meta-analyses were included if at least two of three independent readers regarded their main purpose as the evaluation of diagnostic tests against a concurrent reference standard. DATA EXTRACTION: By three independent readers on the extent to which meta-analyses fulfilled each guideline, with consensus defined as agreement by at least two readers. DATA SYNTHESIS: The guidelines are concerned with determining the objective of the meta-analysis, identifying the relevant literature and extracting the data, estimating diagnostic accuracy, and identifying the extent to which variability is explained by study design characteristics and characteristics of the patients and diagnostic test. In general, the guidelines were only partially fulfilled. CONCLUSION: Meta-analysis is potentially important in the assessment of diagnostic tests. Those reading meta-analyses evaluating diagnostic tests should critically appraise them; those doing meta-analyses should apply recently developed methods. The conduct and reporting of primary studies on which meta-analyses are based require improvement.

Bias↗
PubMed1993

Smoking, alcohol, and plasma levels of carotenes and vitamin E.

Taken together, the results from these studies clearly indicate that alcohol and cigarette smoking may both decrease serum or plasma beta-carotene levels after controlling for dietary intake and lipid profile. The variation among studies in the magnitude of the association and statistical significance may reflect, in part, the joint distribution of smoking and alcohol intake in the populations. For example, in the supplementation study reported by Costantino, 89% consumed alcohol, considerably higher than population averages. Further, one-third of the men in that study consumed more than 65 ml (52 gm) of pure alcohol per day. This contrasts with the data from the Health Professionals Follow-up Study, where the mean intake of alcohol was 12.3 gm/day with a standard deviation of 15.8. Even lower alcohol intakes are reported in women, further attenuating the relation and the statistical power to detect a relation between alcohol and beta-carotene levels. Measurement error in assessing dietary intake of beta-carotene could explain some of the association between smoking, alcohol and serum beta-carotene levels because of incomplete control (residual confounding) of dietary intake. Methods for statistically adjusting for error in measurement have not yet been implemented in analyses of this nature.

Adolescent↗
PubMed1992

Dietary fat and fiber in relation to risk of breast cancer. An 8-year follow-up.

OBJECTIVE: To address the hypotheses that dietary fat increases and fiber decreases the risk of breast cancer. DESIGN: Prospective cohort study with dietary assessment at baseline, using a validated, self-administered food frequency questionnaire. SETTING/PARTICIPANTS: 89,494 women in the Nurses' Health Study who were 34 through 59 years of age in 1980 and who were followed up for 8 years (> 95% complete). RESULTS: 1439 incident cases of breast cancer were diagnosed, including 774 among postmenopausal women. After adjustment for age, established risk factors, and total energy intake, we observed no evidence of any positive association between total fat intake and breast cancer incidence (relative risks [RRs] for increasing quintiles of fat intake were 1.0, 0.85, 0.96, 0.91, and 0.90; 95% confidence interval for highest vs lowest quintile, 0.77 to 1.07). Among postmenopausal women alone, corresponding RRs were 1.0, 0.89, 1.00, 0.95, and 0.91. Comparing extreme deciles of total fat intake (> or = 49% vs < 29% of total energy intake), the RR was 0.86 (95% confidence interval, 0.67 to 1.08). A similar absence of any positive association was observed without adjustment for energy intake; for tumors less than 2 cm as well as 2 cm or greater in diameter; for saturated, monounsaturated, and polyunsaturated fat; and after excluding the first 4 years of follow-up. Also, we found no suggestion of any positive association when using a more detailed and precise dietary questionnaire completed in 1984 (666 subsequent cases), even when women consuming less than 25% of energy from fat were used as the comparison group. No suggestion of a protective effect of dietary fiber was observed (RRs for increasing quintiles were 1.0, 0.95, 0.93, 1.02, and 1.02). CONCLUSIONS: These data provide evidence against both an adverse influence of fat intake and a protective effect of fiber consumption by middle-aged women on breast cancer incidence over 8 years. Nevertheless, the positive association between intake of animal fat and risk of colon cancer observed in many studies provides ample reason to limit this source of energy.

Adult↗
PubMed1992

Relationship of diet to risk of colorectal adenoma in men.

BACKGROUND: Rates of colorectal cancer in various countries are strongly correlated with per-capita consumption of red meat and animal fat and inversely associated with fiber consumption. There have been few studies, however, of dietary risk factors for colorectal adenomas, which are precursors of cancer. PURPOSE: Our purpose was to determine prospectively the relationship between dietary factors and risk of colorectal adenomas. METHODS: Using data from the Health Professionals Follow-up Study, we documented 170 cases of adenomas of the left colon or rectum in 7284 male health professionals who completed a food-frequency questionnaire in 1986 and who had a colonoscopy or sigmoidoscopy between 1986 and 1988. Relative risk (RR) of adenoma was determined according to quintiles of nutrient intakes. RESULTS: After adjustment for total energy intake, saturated fat was positively associated with risk of colorectal adenoma (P for trend = .006); RR for the highest versus the lowest quintile of intake was 2.0 (95% confidence interval [CI] = 1.2-3.2). Dietary fiber was inversely associated with risk of adenoma (P for trend less than .0001); RR for men in the highest versus the lowest quintile was 0.36 (95% CI = 0.22-0.60). All sources of fiber (vegetables, fruits, and grains) were associated with decreased risk of adenoma. For subjects on a high-saturated fat, low-fiber diet, the RR was 3.7 (95% CI = 1.5-8.8) compared with those on a low-saturated fat, high-fiber diet. The ratio of the intake of red meat to the intake of chicken and fish was positively associated with risk of adenoma (P for trend = .02). CONCLUSIONS: These prospective data provide evidence for the hypothesis that a diet high in saturated fat and low in fiber increases the risk of colorectal adenoma. They also support existing recommendations to substitute chicken and fish for red meat in the diet and to increase intake of vegetables, fruits, and grains to reduce risk of colorectal cancer.

Adult↗
PubMed1991

The assessment of alcohol consumption by a simple self-administered questionnaire.

The authors evaluated the reproducibility and validity of alcohol consumption measured by a mailed, self-administered questionnaire in two large prospective studies. Subsamples of 173 women and 136 men from these cohorts completed two food-frequency questionnaires and multiple 1-week diet records (four for women and two for men) and provided a fasting blood sample. Intakes of alcohol reported over the previous year by food frequency questionnaire 2 correlated highly with intake assessed by multiple week diet records completed over this period (Spearman r = 0.90 in women and 0.86 in men). Mean daily alcohol intake as assessed by the diet records and the questionnaires was very similar. Serum high density lipoprotein cholesterol levels were significantly correlated with alcohol intakes estimated from the questionnaire (r = 0.40 in women and 0.35 in men) and for the diet records (r = 0.33 in women and 0.38 in men). Four years after completing the diet records, women were asked to report their alcohol intake of 4 years earlier; this estimate was highly correlated with the diet records (r = 0.84) and with the earlier high density lipoprotein cholesterol (r = 0.40). These data suggest that a simple self-administered questionnaire can provide useful estimates of alcohol intake over an extended period of time in subjects participating in prospective epidemiologic studies.

Adult↗
PubMed1990

Oral contraceptives and breast cancer. Review and meta-analysis.

To evaluate the relation between use of oral contraceptives and the incidence of breast cancer, the authors reviewed the epidemiologic literature and used quantitative methods to summarize the data. Study results for any use of oral contraceptives were pooled using a model that accounted for both interstudy and intrastudy variability. The authors also explored interstudy variability and modeled a duration-effect relation between oral contraceptive use and breast cancer. Case-control and follow-up studies were considered separately. Overall, the authors observed no increase in the risk of breast cancer for women who had ever used oral contraceptives, even after a long duration of use. These results were consistent across study design. However, data combined from case-control studies revealed a statistically significant positive trend (P = 0.001) in the risk of premenopausal breast cancer for women exposed to oral contraceptives for longer duration. This risk was predominant among women who used oral contraceptives for at least 4 years before their first term pregnancy (relative risk = 1.72; 95% confidence interval = 1.36 to 2.19). Additional study is required to determine whether this finding in a subgroup of exposed women is confirmed and whether the risk remains increased with advancing age.

Adult↗
PubMed1990

Coffee, caffeine, and cardiovascular disease in men.

BACKGROUND: For many years, an association between coffee consumption and the risk of coronary heart disease has been suspected. Although based on small numbers of end points, a prospective study has suggested a particularly strong association between recent coffee drinking and the incidence of cardiovascular disease. METHODS: We examined prospectively the relation of coffee consumption with the risk of myocardial infarction, need for coronary-artery bypass grafting or angioplasty, and risk of stroke in a cohort of 45,589 U.S. men who were 40 to 75 years old in 1986 and who had no history of cardiovascular disease. RESULTS: During two years of follow-up observation, 221 participants had a nonfatal myocardial infarction or died of coronary heart disease, 136 underwent coronary-artery surgery or angioplasty, and 54 had a stroke. Total coffee consumption was not associated with an increased risk of coronary heart disease or stroke. The age-adjusted relative risk for all cardiovascular disease among participants who drank four or more cups of coffee per day was 1.04 (95 percent confidence intervals, 0.74 to 1.46). Increasing levels of consumption of caffeinated coffee were not associated with higher risks of cardiovascular disease. Higher consumption of decaffeinated coffee, however, was associated with a marginally significant increase in the risk of coronary heart disease (relative risk, 1.63; 95 percent confidence interval, 1.02 to 2.60). Finally, we observed no pattern of increased risk across the subgroups of participants with increasing intakes of caffeine from all sources. Adjustment for major cardiovascular-risk indicators, dietary intake of fats, and cholesterol intake did not materially alter these associations. CONCLUSIONS: These findings do not support the hypothesis that coffee or caffeine consumption increases the risk of coronary heart disease or stroke.

Adult↗
PubMed1981

Continuing education in general practice. 2. Impact of education activities.

Should continuing education for doctors be compulsory? Our study of General Practitioners in Queensland evaluated the usefulness of and preference for various types of educational activities. Lectures and consultants' letters were considered the most useful while pharmaceutical company evenings and visiting lecturers were most regularly attended. These latter activities were a useful source of medical knowledge: patient management skills were gained at weekend conferences; and procedural skills were obtained through hospital training courses.

Australia↗
PubMed1981

Continuing education in general practice. 1. Attitudes of general practitioners.

As part of a Queensland survey, we made an assessment of the attitudes of general practitioners to continuing education. We analysed responses for age, sex, type and geographical location of practice. Almost all the respondents (99%) agreed that commitment to CME is lifelong. Most of them did not feel that there is too much concern with keeping up-to-date. Recognition of their own educational needs is a problem for a sizeable minority. Most feel that GP skills can be taught through CME courses, which should focus on patient management. Informal communication with colleagues is a useful mode of learning. Although exactly half the doctors felt that CME should be mandatory, a greater proportion of younger doctors were in favour.

Adult↗
PubMedDate not supplied

A qualitative evaluation of the Harvard Cancer Risk Index.

There is an extensive amount of information in the popular press about cancer risk factors. The volume and sometimes contradictory nature of this information makes it difficult for individuals to understand their own level of risk or how one risk factor compares with another. The Harvard Cancer Risk Index (HCRI) was developed by an interdisciplinary working group of epidemiologists and behavioral scientists to educate the public about the major risk factors associated with the 11 most common forms of cancer in the United States. Following the development and validation of the HCRI, we initiated a qualitative research study to obtain initial feedback on the wording and presentation of the index and to elicit information regarding the meaning of risks, perception of cancer, and interpretation of the HCRI results. The results indicated that the HCRI was well received by participants and that they highly regarded the inclusion of information related to the latest risks for cancer and the description of the mechanisms by which these factors impact on risk. Personalization of the risk score helped participants to focus on behaviors that they could change. However, dissatisfaction with the HCRI was noted by some participants because exposures they believed to be important were not included (e.g., poverty, toxic waste, air pollution). Evaluation of the impact of the index on intention to change provided preliminary evidence that this may be an effective toll for helping mobilize individuals toward change across a number of risk factors. Further quantitative evaluation of the HCRI is planned.

Adult↗