Search PubMed⌕ Search

Biomedical subjects

G A Colditz

Publications and source records attributed to G A Colditz.

At least 199 records · Page 11Linked to original sources
PubMed1998

Cigarette smoking, cytochrome P450 1A1 polymorphisms, and breast cancer risk in the Nurses' Health Study.

Environmental exposure to carcinogens may contribute to increasing breast cancer rates and geographic variation in breast cancer incidence in the United States. One class of chemicals that has received much attention are the polyaromatic hydrocarbons that are ubiquitous in the environment and occur in cigarette smoke. The cytochrome P450 1A1 (CYP1A1) gene codes for an enzyme that contributes to aryl hydrocarbon hydroxylase activity, which is involved in the metabolism of polyaromatic hydrocarbons. Genotypic variants of CYP1A1 have been associated with increased aryl hydrocarbon hydroxylase activity, and some epidemiological studies suggest that women with the variant genotype(s) are at increased risk for breast cancer. We prospectively evaluated the associations between the CYP1A1 polymorphisms and breast cancer risk, as well as the potential modification of these associations by cigarette smoking, in a case-control study nested within the Nurses' Health Study. We analyzed the T-->C transition at nucleotide 6235 (MspI) and the A-->G transition at nucleotide 4889 (exon 7) in CYP1A1 by PCR-RFLP assays among 466 incident breast cancer cases and 466 matched controls. Relative risks (RRs) and 95% confidence intervals (CIs) were used to quantify the risk of breast cancer among subjects who had at least one variant allele relative to subjects who were homozygous for the wild-type allele, using conditional logistic regression. No overall increase in breast cancer risk with the variant CYP1A1 genotypes was apparent (RR(MspI), 1.05; 95% CI, 0.74-1.50 and RR(exon7), 0.88; 95% CI, 0.58-1.33). However, a suggestive increase in breast cancer risk was observed among women who had commenced smoking before the age of 18 and had the CYP1A1-MspI variant genotype compared to nonsmokers who were homozygous wild type for the polymorphism (RR, 5.65; 95% CI, 1.50-21.3; percentage of all breast cancer cases attributable to this risk factor, 2.5%). A similar gene-environment association was observed for the exon 7 polymorphism (RR, 3.61; 95% CI, 1.11-11.7; percentage of all breast cancer cases attributable to this risk factor, 2.2%). These data are compatible with the hypothesis that cigarette smoking early in life is a modifiable cause of breast cancer in a subpopulation of genetically susceptible women. However, the proportion of breast cancer attributable to cigarette smoking at a young age among Caucasian women with the variant form of the CYP1A1 polymorphisms is low.

Adult↗
PubMed1998

Folate and vitamin B6 from diet and supplements in relation to risk of coronary heart disease among women.

CONTEXT: Hyperhomocysteinemia is caused by genetic and lifestyle influences, including low intakes of folate and vitamin B6. However, prospective data relating intake of these vitamins to risk of coronary heart disease (CHD) are not available. OBJECTIVE: To examine intakes of folate and vitamin B6 in relation to the incidence of nonfatal myocardial infarction (MI) and fatal CHD. DESIGN: Prospective cohort study. SETTING AND PATIENTS: In 1980, a total of 80082 women from the Nurses' Health Study with no previous history of cardiovascular disease, cancer, hypercholesterolemia, or diabetes completed a detailed food frequency questionnaire from which we derived usual intake of folate and vitamin B6. MAIN OUTCOME MEASURE: Nonfatal MI and fatal CHD confirmed by World Health Organization criteria. RESULTS: During 14 years of follow-up, we documented 658 incident cases of nonfatal MI and 281 cases of fatal CHD. After controlling for cardiovascular risk factors, including smoking and hypertension and intake of alcohol, fiber, vitamin E, and saturated, polyunsaturated, and trans fat, the relative risks (RRs) of CHD between extreme quintiles were 0.69 (95% confidence interval [CI], 0.55-0.87) for folate (median intake, 696 microg/d vs 158 microg/d) and 0.67 (95% CI, 0.53-0.85) for vitamin B6 (median intake, 4.6 mg/d vs 1.1 mg/d). Controlling for the same variables, the RR was 0.55 (95% CI, 0.41-0.74) among women in the highest quintile of both folate and vitamin B6 intake compared with the opposite extreme. Risk of CHD was reduced among women who regularly used multiple vitamins (RR=0.76; 95% CI, 0.65-0.90), the major source of folate and vitamin B6, and after excluding multiple vitamin users, among those with higher dietary intakes of folate and vitamin B6. In a subgroup analysis, compared with nondrinkers, the inverse association between a high-folate diet and CHD was strongest among women who consumed up to 1 alcoholic beverage per day (RR =0.69; 95% CI, 0.49-0.97) or more than 1 drink per day (RR=0.27; 95% CI, 0.13-0.58). CONCLUSION: These results suggest that intake of folate and vitamin B6 above the current recommended dietary allowance may be important in the primary prevention of CHD among women.

Adult↗
PubMed1998

Calcium and fructose intake in relation to risk of prostate cancer.

Laboratory and clinical data indicate an antitumor effect of 1,25(OH)2 vitamin D (1,25(OH)2D) on prostate cancer. High calcium intake suppresses formation of 1,25(OH)2D from 25(OH)D, thereby decreasing the 1,25(OH)2D level. Ingestion of fructose reduces plasma phosphate transiently, and hypophosphatemia stimulates 1,25(OH)2D production. We thus conducted a prospective study among 47,781 men of the Health Professionals Follow-Up Study free of cancer in 1986 to examine whether calcium and fructose intake influenced risk of prostate cancer. Between 1986 and 1994, 1369 non-stage A1 and 423 advanced (extraprostatic) cases of prostate cancer were diagnosed. Higher consumption of calcium was related to advanced prostate cancer [multivariate relative risk (RR), 2.97; 95% confidence interval (CI), 1.61-5.50 for intakes > or = 2000 mg/day versus < 500 mg/day; P, trend, 0.002] and metastatic prostate cancer (RR, 4.57; CI, 1.88-11.1; P, trend, <0.001). Calcium from food sources and from supplements independently increased risk. High fructose intake was related to a lower risk of advanced prostate cancer (multivariate RR, 0.51; CI, 0.33-0.80, for intakes > 70 versus < or = 40 g/day; P, trend, 0.007). Fruit intake was inversely associated with risk of advanced prostate cancer (RR, 0.63; 95% CI, 0.43-0.93; for > 5 versus < or = 1 serving per day), and this association was accounted for by fructose intake. Non-fruit sources of fructose similarly predicted lower risk of advanced prostate cancer. A moderate positive association between energy-adjusted fat intake and advanced prostate cancer was attenuated and no longer statistically significant when controlled for calcium and fructose. Our findings provide indirect evidence for a protective influence of high 1,25(OH)2D levels on prostate cancer and support increased fruit consumption and avoidance of high calcium intake to reduce the risk of advanced prostate cancer.

Adult↗
PubMed1998

Body weight, weight change, and risk for hypertension in women.

BACKGROUND: Obesity increases the risk for hypertension, but the effects of modest long-term weight changes have not been precisely quantified. OBJECTIVE: To investigate body mass index (BMI) and weight change in relation to risk for hypertension. DESIGN: Cohort study. SETTING: General community. PARTICIPANTS: Cohort of 82,473 U.S. female nurses 30 to 55 years of age followed every 2 years since 1976. The follow-up rate was 95%. MEASUREMENTS: Primary risk factors examined were 1) BMI at age 18 years and midlife and 2) long-term and medium-term weight changes. The outcome was incident cases of hypertension. RESULTS: By 1992, 16,395 incident cases of hypertension had been diagnosed. After adjustment for multiple covariates, BMI at 18 years of age and midlife were positively associated with occurrence of hypertension (P for trend < 0.001). Long-term weight loss after 18 years of age was related to a significantly lower risk for hypertension, and weight gain dramatically increased the risk for hypertension (compared with weight change < or = 2 kg, multivariate relative risks were 0.85 for a loss of 5.0 to 9.9 kg, 0.74 for a loss > or = 10 kg, 1.74 for a gain of 5.0 to 9.9 kg, and 5.21 for a gain > or = 25.0 kg). Among women in the top tertile of baseline BMI at age 18 years, weight loss had a greater apparent benefit. The association between weight change and risk for hypertension was stronger in younger (< 45 years of age) than older women (> or = 55 years of age). Medium-term weight changes after 1976 showed similar relations to risk for hypertension. CONCLUSIONS: Excess weight and even modest adult weight gain substantially increase risk for hypertension. Weight loss reduces the risk for hypertension.

Adult↗
PubMed1998

Current estimates of the economic cost of obesity in the United States.

This study was undertaken to update and revise the estimate of the economic impact of obesity in the United States. A prevalence-based approach to the cost of illness was used to estimate the economic costs in 1995 dollars attributable to obesity for type 2 diabetes mellitus, coronary heart disease (CHD), hypertension, gallbladder disease, breast, endometrial and colon cancer, and osteoarthritis. Additionally and independently, excess physician visits, work-lost days, restricted activity, and bed-days attributable to obesity were analyzed cross-sectionally using the 1988 and 1994 National Health Interview Survey (NHIS). Direct (personal health care, hospital care, physician services, allied health services, and medications) and indirect costs (lost output as a result of a reduction or cessation of productivity due to morbidity or mortality) are from published reports and inflated to 1995 dollars using the medical component of the consumer price index (CPI) for direct cost and the all-items CPI for indirect cost. Population-attributable risk percents (PAR%) are estimated from large prospective studies. Excess work-lost days, restricted activity, bed-days, and physician visits are estimated from 88,262 U.S. citizens who participated in the 1988 NHIS and 80,261 who participated in the 1994 NHIS. Sample weights have been incorporated into the NHIS analyses, making these data generalizable to the U.S. population. The total cost attributable to obesity amounted to $99.2 billion dollars in 1995. Approximately $51.64 billion of those dollars were direct medical costs. Using the 1994 NHIS data, cost of lost productivity attributed to obesity (BMI> or =30) was $3.9 billion and reflected 39.2 million days of lost work. In addition, 239 million restricted-activity days, 89.5 million bed-days, and 62.6 million physician visits were attributable to obesity in 1994. Compared with 1988 NHIS data, in 1994 the number of restricted-activity days (36%), bed-days (28%), and work-lost days (50%) increased substantially. The number of physician visits attributed to obesity increased 88% from 1988 to 1994. The economic and personal health costs of overweight and obesity are enormous and compromise the health of the United States. The direct costs associated with obesity represent 5.7% of our National Health Expenditure in the United States.

Coronary Disease↗
PubMed1998

Blood pressure in adolescence and early adulthood related to obesity and birth size.

OBJECTIVE: Obesity is an established risk factor for higher systolic (SBP) and diastolic (DBP) blood pressure in adolescence and early adulthood, but birth size may also have a role. We analyzed the effects of adolescent and adult obesity and birth size on BP in the young adult. RESEARCH METHODS AND PROCEDURES: In a prospective longitudinal study, anthropometric measurements were obtained at birth on 67 boys and 67 girls born in Boston. Their body mass indices (BMI) and BP were recorded 17 years and 30 years later. RESULTS: For women, adolescent and early adult obesity appeared to be the stronger determinants of higher BP, although smaller head and chest circumferences at birth may also be related. We found some evidence of birth (ponderal index [PI] and head circumference) anthropometric influences on age 17 BP levels in boys. By age 30, body mass variables were the dominant predictors of male BP levels. Female BMI at age 17 was positively correlated with birth adiposity (PI), but BMI at 30 was related only to age 17 BMI. Similarly, male BMI at 17 years was higher for those who weighed more at birth, but BMI at 30 years was again related only to age 17 BMI. DISCUSSION: We conclude that adult weight and weight gain are the major determinants of adult BP.

Adipose Tissue↗
PubMed1998

A prospective study of reproductive factors and oral contraceptive use in relation to the risk of uterine leiomyomata.

OBJECTIVE: To investigate the risk of uterine leiomyomata in relation to reproductive factors and oral contraceptive use. DESIGN: A prospective study. SETTING: A cohort of female registered nurses from 14 states in the United States who completed mailed questionnaires in 1989, 1991, and 1993. PATIENT(S): Premenopausal nurses (n=95,061) aged 25-42 years with intact uteri and no history of diagnosed uterine leiomyomata or cancer in 1989. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Incidence of self-reported uterine leiomyomata confirmed by ultrasound or hysterectomy. In a sample of 243 cases, 93% of the self-reported diagnoses were confirmed in the medical record. RESULT(S): During 326,116 person-years of follow-up, 3,006 cases of uterine leiomyomata, confirmed by ultrasound or hysterectomy, were reported. After adjustment for other risk factors, the risk of uterine leiomyomata was significantly inversely associated with age at menarche, parity, and age at first birth, and positively associated with a history of infertility and years since last birth. The only notable association with any aspect of oral contraceptive use was a significantly elevated risk among women who first used oral contraceptives at ages 13-16 years compared with those who had never used oral contraceptives. CONCLUSION(S): Reproductive factors and oral contraceptive use at a young age influence the risk of uterine leiomyomata among premenopausal women.

Adult↗
PubMed1998

Distinction between symptoms of voiding and filling in benign prostatic hyperplasia: findings from the Health Professionals Follow-up Study.

OBJECTIVES: There is debate about the validity of the clinical distinction between filling and voiding symptoms of benign prostatic hyperplasia (BPH). We examined empirically the evidence for the existence of these clinical constructs. METHODS: We analyzed responses to the American Urological Association Symptom Index (AUA SI) among men from a large cohort sample (the Health Professionals Follow-up Study, n = 7753) and a subsample with physician-diagnosed BPH (n = 1856). We used factor analysis, which is a data reduction tool that allowed us to determine empirically the relationships among lower urinary tract symptoms thought to be clinically related by pathogenesis, physiology, or treatment response. RESULTS: The results of the factor analysis indicated that responses to the AUA SI items could be grouped into one of two subscales: one describing voiding problems and the other describing filling problems. Analyses of internal consistency reliability indicated that the AUA SI as well as the filling and voiding subscales have sound internal reliability. CONCLUSIONS: We found empirical support for the clinical conceptualization of lower urinary tract symptoms into filling and voiding problems. These findings provide support for using the total score on the AUA SI as a reliable measure of overall symptom severity in BPH, as well as for separately summing the voiding and filling items to measure these distinctive types of lower urinary tract symptomatology. Further research is needed to determine whether these symptom groupings better distinguish responses to one treatment type over another. If so, targeting treatment based on the relative severity of voiding and filling symptoms might improve patient outcomes.

Aged↗
PubMed1998

Response to a mail nutritional survey in an older bi-racial community population.

PURPOSE: We conducted a pilot study of a mail food frequency questionnaire among a bi-racial sample of 200 persons 65 years and older, selected from participants of an ongoing community study. METHODS: Up to three successive mailings were followed by personal contact with nonresponders. Response to the mail survey was higher in whites (81%) than in blacks (53%). Personal contact was important to achieving high and uniform response (94%) in both racial groups. RESULTS: Those responding to the mailed questionnaires were also more likely to be older and higher educated. The vast majority of questionnaires returned by mail were complete; 85% had fewer than 15 missing items out of 152 questions. CONCLUSIONS: A mail nutritional survey is a feasible method of dietary assessment in older, white populations, but personal contact with nonresponders may be required for comparable participation among blacks.

Black or African American↗
PubMed1998

Diabetes mellitus and risk of prostate cancer (United States).

A lower risk of prostate cancer among diabetics has been suggested by several but not all studies. However, the studies have not always accounted for time since diagnosis of diabetes mellitus, or have not examined confounding factors such as diet and diagnostic bias. We thus examined this relationship in the Health Professionals Follow-Up Study from 1986 and 1994, in which 1,369 new cases of non-stage A1 prostate cancer were documented in 47,781 men. A prior history of a diagnosis of diabetes (mostly adult-onset) was associated with a reduced risk of prostate cancer (multivariate relative risk [RR] = 0.75; 95 percent confidence interval [CI] = 0.59-0.95) controlling for age, body mass index (wt/ht2) at age 21, and, in 1986, race, vasectomy, and intakes of total energy, total fat, calcium, fructose, and lycopene. After excluding the first year of follow-up after the diagnosis of diabetes, the RR was 0.63 (CI = 0.54-0.89). Prostate cancer was not reduced in the first five years after diagnosis (RR = 1.24, CI = 0.87-1.77), but was lower in the next five years (RR = 0.66, CI = 0.39-1.10) and lowest after 10 years (RR = 0.54, CI = 0.37-0.78); P-value for trend across time = 0.004. Similar associations were noted for advanced cases. Detection bias was unlikely to account for our findings. The basis of this relationship is unclear but may reflect hormonal changes related to diabetes, perhaps low testosterone levels.

Adult↗
PubMed1998

Screening endoscopy and risk of colorectal cancer in United States men.

OBJECTIVES: The purpose of this study was to describe the effect of screening endoscopy (sigmoidoscopy or colonoscopy) on colorectal cancer incidence and mortality. METHODS: We used data from a prospective cohort study of 24,744 men aged 40 to 75 years in 1986, free from cancer and colon polyps, followed until 1994. The outcomes are diagnosis of colorectal cancer and death from colorectal cancer. RESULTS: Screening endoscopy in 1986-87 was associated with a lower risk of all colorectal cancer (multivariate relative risk [RR] = 0.58, 95 percent confidence interval [CI] = 0.36-0.96); cancer in the distal colon or rectum (multivariate RR = 0.40, CI = 0.19-0.84); Dukes stage A&B (multivariate RR = 0.66, CI = 0.35-1.25); and Dukes stage C&D (multivariate RR = 0.50, CI = 0.20-1.26) colorectal cancer; and death from colorectal cancer (multivariate RR = 0.56, CI = 0.20-1.60), after adjusting for age and a wide range of colon cancer risk factors. Screening endoscopy in 1988-87 appeared to provide strong protection against distal stage C&D cancers (age-adjusted RR = 0.16, CI = 0.02-1.23) but no protection against proximal stage C&D cancers (age-adjusted RR = 0.96, CI = 0.32-2.91). CONCLUSIONS: This study provides strong evidence for a protective effect of screening sigmoidoscopy on colorectal cancer incidence and mortality and supports recommendations for screening sigmoidoscopy as an approach to colon cancer prevention.

Adult↗
PubMed1998

Lower levels of physical functioning are associated with higher body weight among middle-aged and older women.

OBJECTIVE: To compare levels of physical function, across levels of body mass index (BMI), among middle- to older-aged women. DESIGN: Cross-sectional study. Physical function, body weight and other covariates were measured in 1992. SUBJECTS: 56510 women aged 45-71 y, free of cardiovascular disease and cancer, participating in the Nurses' Health Study. MAIN OUTCOME MEASURES: The four physical function scores on the Medical Outcomes Study (MOS) Short Form-36 (SF36) Health Survey: physical functioning, vitality, bodily pain and role limitations. RESULTS: After adjusting for age, race, smoking status, menopausal status, physical activity and alcohol consumption, there was a significant dose-response gradient between increasing levels of BMI in 1992 and reduced function. For example, women with a BMI between 30-34.9 kg/m2 averaged: 9.0 point lower physical functioning score (95% Confidence interval (CI) -9.5, -8.5), 5.6 point lower vitality score (95% CI: -6.1, -5.1), and 7.0 point lower freedom from pain score (95% CI: -7.6, -6.4). These declines represent an approximate 10% loss of function compared to the reference category of women with BMIs ranging from 22.0-23.9 kg/m2. For the same BMI comparison, heavier women were at 66% increased risk of limitations in ability to work or perform other roles (RR = 1.66; 95% odds ratio (OR) CI: 1.56, 1.76). These findings were replicated when the sample was restricted to women who had maintained their BMI over a ten year period. CONCLUSIONS: In addition to increasing risk of chronic health conditions, greater adiposity is associated with lower every day physical functioning, such as climbing stairs or other moderate activities, as well as lower feelings of well-being and greater burden of pain.

Aged↗
PubMed1998

The relation between dietary intake and adipose tissue composition of selected fatty acids in US women.

We compared fatty acid amounts in adipose tissue with fatty acid intake calculated from 2 separate weeks of diet recording and two food-frequency questionnaires for 140 participants in the Nurses' Health Study. Our results showed that the amounts of polyunsaturated and trans fatty acids in adipose tissue reflect dietary intake and confirm those of previous studies. The correlation between the polyunsaturated fatty acid content of adipose tissue and polyunsaturated fatty acid intake from the average of the two food-frequency questionnaires was 0.40; this correlation for trans fatty acids was also 0.40. Linolenic acid amounts in adipose tissue were also moderately correlated with intake from the average of the food-frequency questionnaires (r = 0.34). An estimate of trans fatty acid intake from vegetable sources correlated much more strongly with adipose trans fatty acids than did an estimate of trans fatty acids from animal sources. Adipose tissue aspirates can be used to indicate intake of exogenous fatty acids.

Adipose Tissue↗
PubMed1998

Has high-frequency ventilation been inappropriately discarded in adult acute respiratory distress syndrome?

OBJECTIVES: To review the basic physiologic principles that support the role for high-frequency ventilation (HFV) in acutely lung-injured patients, to critically assess clinical trial data in this area, and discuss why a metasummary is not feasible and a large-scale clinical trial is needed. DATA SOURCES: We searched a computerized database (MEDLINE) from 1976 to January 1997 using the text words "high-frequency ventilation" and "acute respiratory distress syndrome" to retrieve all relevant candidate articles. STUDY SELECTION: We retrieved all English language clinical studies conducted in tertiary care centers that employed HFV in adult acute respiratory distress syndrome (ARDS) patients. DATA EXTRACTION: Only prospective, randomized trials, cohort/case-control studies, and case series evaluating HFV vs. conventional mechanical ventilation in adult ARDS patients were included. DATA SYNTHESIS: We independently screened 3,166 articles on ARDS and 494 papers on HFV in our computer search. We checked reference lists and contacted experts in the field of mechanical ventilation in ARDS to ensure that no relevant studies had been missed. Only four articles met our inclusion criteria and were evaluated in detail. CONCLUSIONS: Current clinical studies are statistically under-powered and a metasummary is not feasible because of study quality, as well as lack of similar clinical end points and measures of magnitude of benefit. A large, multicenter trial should be initiated to define the role of HFV in the treatment of adult ARDS.

Adult↗
PubMed1998

Comparison of 4 questionnaires for assessment of fruit and vegetable intake.

OBJECTIVE: This study compared fruit and vegetable assessments derived from 4 self-administered questionnaires. METHODS: Among 102 adolescents, servings of fruits and vegetables assessed by 4 questionnaires were compared with estimates from 24-hour recalls. RESULTS: The prevalence of consuming 5 or more servings of fruits and vegetables a day was underestimated by the questionnaires. Questionnaires asking subjects to recall their diet over the previous year were more effective in ranking subjects (r's > or = .42) than those assessing previous-day diet (r's > or = .30). CONCLUSIONS: Brief assessments of fruit and vegetable intake are more useful for ranking subjects than for estimating prevalence of consumption of 5 or more servings per day.

Adolescent↗
PubMed1998

Relationship of job strain and iso-strain to health status in a cohort of women in the United States.

OBJECTIVE: This study examined the relationships of job strain and iso-strain psychosocial work-environment exposures to health status in a cohort of working women in the United States. METHODS: In a cross-sectional survey, 33689 women responded to the Karasek job content and the MOS SF-36 health status questionnaires. The psychosocial work-environment exposures were characterized using the job strain and iso-strain frameworks. Health status was assessed with the following 6 scales: physical functioning, vitality, freedom from pain, mental health, role limitations due to physical health, and role limitations due to emotional health. RESULTS: When compared with active work, high-strain work (high job demands and low job control) was associated with lower vitality, mental health, higher pain, and increased risks of both physical and emotional role limitations. Iso-strain work (high strain and low work-related social support) increased the risks further. Job insecurity was also associated with lower health status. CONCLUSIONS: The analyses supported the hypothesis that the psychosocial work environment is an important determinant of health status among working women. The findings suggest that incorporating social conditions at work into the measurement of psychosocial work-environment exposure improves the identification of high-risk work arrangements.

Adult↗
PubMed1998

Tooth loss and hormone use in postmenopausal women.

Nearly 32% of US women aged 65 to 69 have no teeth. Because some tooth loss may reflect systemic osteoporosis, and postmenopausal hormone therapy protects against osteoporosis, the authors examined the risk of tooth loss in relation to hormone use in a prospective study of 42,171 postmenopausal women. Overall, the risk of tooth loss was 24% lower in women who were currently using hormones, although there was little effect for women who had stopped taking hormones. This decreased risk for current hormone users was observed regardless of the duration of use and was similar for a variety of hormone preparations and doses. Although few studies have examined the issue, this research suggests that hormone therapy may reduce tooth loss.

Age Factors↗