Physical activity and colorectal cancer

Physical activity has been inconsistently associated with rectal cancer despite the consistent association between physical activity and colon cancer. In this study, the authors evaluated the association between physical activity and rectal cancer using the same questionnaire used to evaluate the previously reported association with colon cancer. A population-based study of 952 incident cases of cancer in the rectum and rectosigmoid junction and 1,205 age- and sex-matched controls was conducted in Utah and northern California at the Kaiser Permanente Medical Care Program between 1997 and 2002. Vigorous physical activity was associated with reduced risk of rectal cancer in both men and women (odds ratio (OR) = 0.60, 95% confidence interval (CI): 0.44, 0.81 for men; OR = 0.59, 95% CI: 0.40, 0.86 for women). Among men, moderate levels of physical activity also were associated with reduced risk of rectal cancer (OR = 0.70, 95% CI: 0.51, 0.97). Participation in vigorous activity over the past 20 years conferred the greatest protection for both men and women (OR = 0.55, 95% CI: 0.39, 0.78 for men; OR = 0.44, 95% CI: 0.30, 0.67 for women). In summary, physical activity was associated with reduced risk of rectal cancer in these data. The reduced risk was similar to that previously observed for colon cancer.     

Energy Balance and Rectal Cancer: An Evaluation of Energy Intake,Energy Expenditure,and Body Mass Index

Lack of energy balance, or greater energy intake than expenditure as indicated by a large body mass index (BMI), has been associated with colon cancer, although less is known about its association with rectal cancer. In this study, we examined the association between BMI, energy intake, and energy expenditure and their combined effect on rectal cancer risk. A population-based case-control study was conducted in Utah and Northern California. Incident cases (n = 952) of rectal cancer and population-based controls (n = 1205) were interviewed between 1997 and 2002 to obtain detailed information on body size, dietary intake, and physical activity patterns. BMI (kg/m2) was not associated with rectal cancer in either men or women. Participation in vigorous leisure-time physical activity over the past 20 yr was associated with a significant 40% reduction in rectal cancer risk. Energy intake was associated significantly with increased risk of rectal cancer, especially among people whose diagnosis was prior to age 60 yr (odds ratio [OR] = 3.9; 95% confidence interval [CI] = 1.7-9.1 for men; OR = 2.8; 95% CI = 1.1-7.2 for women). There was a significant interaction between energy intake and energy expenditure, although not between BMI and either energy intake or energy expenditure. These data suggest that large BMI, an indicator of lack of energy balance, is not an important component of the etiology of rectal cancer. However, both physical activity and energy intake were significantly associated with rectal cancer risk. These data suggest that energy expenditure and energy intake alter rectal cancer risk through mechanisms other than energy balance.     

Energy balance and rectal cancer: an evaluation of energy intake, energy expenditure, and body mass index

Lack of energy balance, or greater energy intake than expenditure as indicated by a large body mass index (BMI), has been associated with colon cancer, although less is known about its association with rectal cancer. In this study, we examined the association between BMI, energy intake, and energy expenditure and their combined effect on rectal cancer risk. A population-based case-control study was conducted in Utah and Northern California. Incident cases (n = 952) of rectal cancer and population-based controls (n = 1205) were interviewed between 1997 and 2002 to obtain detailed information on body size, dietary intake, and physical activity patterns. BMI (kg/m(2)) was not associated with rectal cancer in either men or women. Participation in vigorous leisure-time physical activity over the past 20 yr was associated with a significant 40% reduction in rectal cancer risk. Energy intake was associated significantly with increased risk of rectal cancer, especially among people whose diagnosis was prior to age 60 yr (odds ratio [OR] = 3.9; 95% confidence interval [CI] = 1.7-9.1 for men; OR = 2.8; 95% CI = 1.1-7.2 for women). There was a significant interaction between energy intake and energy expenditure, although not between BMI and either energy intake or energy expenditure. These data suggest that large BMI, an indicator of lack of energy balance, is not an important component of the etiology of rectal cancer. However, both physical activity and energy intake were significantly associated with rectal cancer risk. These data suggest that energy expenditure and energy intake alter rectal cancer risk through mechanisms other than energy balance.     

Body mass index and colon cancer in a national sample of adult US men and women.

The evidence supporting obesity as a risk factor for colon cancer remains inconclusive, especially among women. The author studied the association between obesity and colon cancer in a nationally representative cohort of men and women aged 25-74 years who participated in the First National Health and Nutrition Examination Survey from 1971 to 1975 and were subsequently followed up through 1992. Among the 13,420 persons included in the analytic sample, 222 incident cases of colon cancer were identified. Height and weight were measured during the baseline examination. Compared with participants whose body mass index was less than 22 kg/m2, the hazard ratios were 1.79 (95% confidence interval (CI): 0.87, 3.71), 1.86 (95% CI: 0.86, 4.03), 2.47 (95% CI: 1.14, 5.32), 3.72 (95% CI: 1.68, 8.22), and 2.79 (95% CI: 1.22, 6.35) for participants with a body mass index of 22-<24 kg/m2, 24-<26 kg/m2, 26-<28 kg/m2, 28-<30 kg/m2, and > or = 30 kg/m2, respectively. The hazard ratios were similar for men and women. Subscapular skinfold thickness, but not triceps skinfold thickness, was positively associated with colon cancer incidence among men but not women, after adjustment for body mass index and other possible confounders. These results strongly support the hypothesis that excess body weight is a risk factor for colon cancer among both men and women.     

Risk factors for renal cell cancer: the multiethnic cohort

The association of body size, lifestyle, and medical conditions with renal cell cancer risk was examined among 161,126 Hawaii-Los Angeles Multiethnic Cohort participants (1993-2002). After 8.3 years of follow-up, 347 renal cell cancer cases (220 men, 127 women) were identified. Renal cell cancer risk increased with increasing body mass index in men (multivariate relative risk (RR) = 1.06 per unit of body mass index, p = 0.001) and women (RR = 1.07, p < 0.0001). The relative risks associated with being obese compared with being lean were 1.76 (95% confidence interval (CI): 1.20, 2.58) for men and 2.27 (95% CI: 1.37, 3.74) for women. Hypertension was associated with renal cell cancer (RR-men = 1.42, 95% CI: 1.07, 1.87; RR-women = 1.58, 95% CI: 1.09, 2.28). Smoking was confirmed to be a risk factor for both sexes. Among women, diuretic use was associated with increased risk (RR = 1.63, 95% CI: 1.04, 2.57), whereas physical activity was associated with reduced risk (ptrend = 0.027). Alcohol consumption was inversely associated with risk for men (ptrend = 0.045). Compared with nondrinkers, men who drank >or=1 drinks/day had a 31% lower risk (95% CI: 0.49, 0.96). Results show that body mass index, smoking, and hypertension are risk factors for renal cell cancer in both sexes.     

Obesity and colon and rectal cancer risk: a meta-analysis of prospective studies

BACKGROUND: Whereas obesity has been associated with an increased risk of colon cancer in men, a weak or no association has been observed in women. Results for rectal cancer have also been inconsistent. OBJECTIVE: The objective was to perform a meta-analysis to summarize the available evidence from prospective studies on the associations of overall and abdominal obesity with the risk of colon and rectal cancer. DESIGN: We searched MEDLINE (1966-April 2007) and the references of the retrieved articles. Study-specific relative risks (RRs) were pooled by using a random-effects model. RESULTS: Thirty prospective studies were included in the meta-analysis of body mass index (BMI; in kg/m(2)). Overall, a 5-unit increase in BMI was related to an increased risk of colon cancer in both men (RR: 1.30; 95% CI: 1.25, 1.35) and women (RR: 1.12; 95% CI: 1.07, 1.18), but the association was stronger in men (P < 0.001). BMI was positively associated with rectal cancer in men (RR: 1.12; 95% CI: 1.09, 1.16) but not in women (RR: 1.03; 95% CI: 0.99, 1.08). The difference in RRs between cancer sites was statistically significant (P < 0.001 in men and P = 0.04 in women). Colon cancer risk increased with increasing waist circumference (per 10-cm increase) in both men (RR: 1.33; 95% CI: 1.19, 1.49) and women (RR: 1.16; 95% CI: 1.09, 1.23) and with increasing waist-hip ratio (per 0.1-unit increase) in both men (RR: 1.43; 95% CI: 1.19, 1.71) and women (RR: 1.20; 95% CI: 1.08, 1.33). CONCLUSIONS: The association between obesity and colon and rectal cancer risk varies by sex and cancer site.     

Body size and colorectal cancer risk after 16.3 years of follow-up: an analysis from the Netherlands Cohort Study

A large body size may differentially influence risk of colorectal cancer (CRC) by anatomic location. The Netherlands Cohort Study includes 120,852 men and women aged 55-69 years who self-reported weight, height, and trouser/skirt size at baseline (1986), as well as weight at age 20 years. Derived variables included body mass index (BMI; weight (kg)/height (m)(2)), BMI at age 20 years, and BMI change. After 16.3 years of follow-up (1986-2002), 2,316 CRC cases were available for case-cohort analysis. In men, the highest risk estimates were observed for body fat (per 5-unit increase in BMI, hazard ratio (HR) = 1.25, 95% confidence interval (CI): 1.05, 1.46; for highest quintile of trouser size vs. lowest, HR = 1.63, 95% CI: 1.17, 2.29 (P-trend = 0.02)) and appeared more closely associated with distal colon tumors (for BMI (5-unit increase), HR = 1.42, 95% CI: 1.13, 1.79; for highest quintile of trouser size, HR = 2.56, 95% CI: 1.55, 4.24 (P-trend < 0.01)) than with proximal colon or rectal tumors. In women, body fat was not associated with CRC risk unless it was considered simultaneously with physical activity; a large trouser/skirt size and a low level of physical activity increased risk for all subtypes. Height was associated with risk of CRC, especially distal colon tumors (highest quintile vs. lowest: HR = 1.53, 95% CI: 1.03, 2.27; P-trend = 0.05), in women only.     

Benefits of leisure-time physical activity on the cardiovascular risk profile at older age.

BACKGROUND: Intensity, frequency and duration of physical activity may contribute in different ways to the maintenance of cardiovascular health. Their relative importance may also change at different stages in life and this should be taken into account for activity recommendations. METHODS: The relationship of frequency and duration of leisure-time physical activities with cardiovascular risk factors was studied in 4942 male and 5885 female participants aged 50-69, of the German Cardiovascular Prevention Study (1984-1991). RESULTS: After adjustment for several possible confounders, women with modest levels (2-12 times per month, 0.5-2 h per week) of moderate-to-vigorous activity (> or =5 kcal/kg/h) had significantly lower systolic blood pressure (-1.8%), resting heart rate (-3.1%) and body mass index (-3.2%) values than sedentary women. Beneficial differences increased with frequency and duration of activity. Light activities (3-4.5 kcal/kg/h), conducted > or =5 times a week, were significantly associated with favourable lower diastolic blood pressure (-1.4%), resting heart rate (-2.3%) among women, and body mass index (women -2.9%, men -2.2%) among both genders. Recommended activity levels (> or =5 times, > or =3.5 h weekly) were associated with a lower prevalence of multiple risk factors (odds ratio [OR] = 0.55, 95% CI: 0.41-0.75 for men and OR = 0.44 95% CI: 0.31-0.63 for women). CONCLUSIONS: For sedentary elderly, even less physical activity than currently recommended, is likely to improve the cardiovascular risk profile.     

Diabetes Mellitus and Site-specific Colorectal Cancer Risk in Korea: A Case-control Study

Objectives:

Previous large-scale cohort studies conducted in Korea have found a positive association between diabetes mellitus (DM) and colorectal cancer (CRC) in men only, in contrast to studies of other populations that have found significant associations in both men and women.

Methods:

A total of 1070 CRC cases and 2775 controls were recruited from the National Cancer Center, Korea between August 2010 and June 2013. Self-reported DM history and the duration of DM were compared between cases and controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by binary and polytomous logistic regression models.

Results:

DM was associated with an elevated risk of CRC in both men (OR, 1.47; 95% CI, 1.13 to 1.90) and women (OR, 1.92; 95% CI, 1.24 to 2.98). This association remained when we controlled for age, body mass index, alcohol consumption, and physical activity level. In sub-site analyses, DM was associated with distal colon cancer risk in both men (multivariate OR, 2.04; 95% CI, 1.39 to 3.00) and women (multivariate ORs, 1.99; 95% CI, 1.05 to 3.79), while DM was only associated with rectal cancer risk in women (multivariate OR, 2.05; 95% CI, 1.10 to 3.82). No significant association was found between DM and proximal colon cancer risk in either men (multivariate OR, 1.45; 95% CI, 0.88 to 2.41) or women (multivariate OR, 1.79; 95% CI, 0.78 to 4.08).

Conclusions:

Overall, DM was associated with an increased risk of CRC in Koreans. However, potential over-estimation of the ORs should be considered due to potential biases from the case-control design.     

Body mass index and risk of renal cell carcinoma

To examine the association between body mass index and renal cell carcinoma risk, we analyzed data from a case-control study of members of a health maintenance organization in western Washington State. We identified cases diagnosed between 1980 and 1995 through a population-based cancer registry. We selected controls from membership files. We collected adult weight and height from medical records. Increased body mass index was associated with increases in risk for both men and women (for the top quartile relative to the bottom quartile of maximum body mass index: in women, OR = 3.3, 95% CI = 1.2-8.7; in men, OR = 2.3, 95% CI = 1.2-4.5).     

Smoking and body mass in the natural history of physical activity: prospective evidence from the Alameda County Study, 1965-1974

The prospective effects of smoking status and body mass on change in leisure-time physical activity from 1965 to 1974 were examined in a cohort of 4,622 persons 20-94 years of age from the Alameda County Study. With adjustment for age and baseline physical activity, current smokers showed a greater nine-year decline in leisure-time physical activity than those who had never smoked. The coefficient for current smokers from a multivariate linear regression model was of a similar magnitude among women and men (coefficient = -0.27, 95% confidence interval [CI] = -0.50 to -0.05 for women; coefficient = -0.26, 95% CI = -0.54 to 0.02 for men). Larger declines in physical activity were seen with increasing number of current pack-years exposure among both women and men. Compared with women of average body mass index, women of heaviest body mass index had larger declines (coefficient = -0.70, 95% CI = -1.04 to -0.36) while women of the lightest body mass index had larger increases (or smaller declines) in physical activity (coefficient = 0.33, 95% CI = 0.00 to 0.66). Although body mass index did not initially appear to be associated with a change in physical activity among men, age-specific analyses indicated that the effect of body mass index on physical activity varied with age such that younger (20-39 years of age), thinner men increased their activity, while older (60 years of age and over), thinner men decreased their physical activity more than men of the same age with average body mass index.     

Body size and breast cancer risk in black women and white women: the Carolina Breast Cancer Study

The relation between body size and breast cancer risk was investigated in a population-based, case-control study of Black women (350 cases, 353 controls) and White women (523 cases, 471 controls) from North Carolina, aged 20-74 years in 1993-1996. Logistic regression analyses compared tertiles of each body size variable, adjusting for age and breast cancer risk factors (results shown for highest relative to lowest tertile). Among premenopausal women, body mass index (kg/m2) was inversely associated with breast cancer (odds ratio (OR) = 0.46, 95% confidence interval (CI): 0.26, 0.80) for Whites but not for Blacks. There was essentially no association among postmenopausal women. Higher waist/hip ratio, adjusted for body mass index, increased risk for all women. Odds ratios for Black and White premenopausal women were 2.50 (95% CI: 1.10, 5.67) and 2.44 (95% CI: 1.17, 5.09), respectively; odds ratios for Black and White postmenopausal women were 1.62 (95% CI: 0.70, 3.79) and 1.64 (95% CI: 0.88, 3.07), respectively. Findings for body mass index differed among Black women when stratified by age (<50 years) (OR = 0.50, 95% CI: 0.25, 1.01) instead of menopausal status. Thus, the associations of breast cancer with body mass index and waist/hip ratio among Black women are similar to those documented for Whites, despite different body size profiles on average.     

Assessing the value of customized birth weight percentiles

Aspirin use decreases colon cancer risk, but this association may vary among population subgroups. The aspirin-colon cancer association was evaluated according to body mass index and physical activity in 1,701 incident colon cancer cases diagnosed during follow-up of 139,310 participants for up to 26 years in 2 US prospective cohort studies that began in 1980 and 1992, respectively. Whether plasma C-peptide levels modified the association was examined by using a nested case-control design (n = 384 cases, 749 controls). Multiplicative and additive interactions were tested. Body mass index did not modify the association; pooled multivariable relative risks for regular aspirin use versus nonuse ranged from 0.74 to 0.75 in the normal weight and obese groups (test for multiplicative interaction, P = 0.75; test for additive interaction, P = 0.66). Pooled multivariable relative risks for regular aspirin use were 0.86 (95% confidence interval (CI): 0.66, 1.11) in the low and 0.67 (95% CI: 0.58, 0.77) in the high physical activity groups with no interaction evident on either the multiplicative or additive scale (P > 0.10). Plasma C-peptide levels also did not modify the aspirin-colon cancer association, with multivariable relative risks of 0.74 (95% CI: 0.50, 1.10) for the low and 0.65 (95% CI: 0.46, 0.92) for the high group. Reductions in colon cancer risk associated with aspirin use were not significantly modified by body mass index, physical activity, or plasma C-peptide level in this study.     

Body mass index and colon cancer mortality in a large prospective study

Obesity has been reported to increase the risk of colon cancer, especially in men. The authors examined this relation in the American Cancer Society's Cancer Prevention Study II, a nationwide mortality study of US adults. After 12 years of follow-up, 1,616 deaths from colon cancer in women and 1,792 in men were observed among 496,239 women and 379,167 men who were cancer free at enrollment in 1982. The authors used Cox proportional hazards analyses to control for effects of age, race, education, smoking, exercise, alcohol, parental history of colon cancer, fat intake, vegetable and grain intake, aspirin use and, in women, estrogen replacement therapy. In men, death rates from colon cancer increased across the entire range of body mass index (BMI). The rate ratio was highest for men with BMI > or =32.5 (rate ratio (RR) = 1.90, 95% confidence interval (CI): 1.46, 2.47) compared with men with BMI between 22.00 and 23.49. In women, a weaker association was seen in the three BMI categories of 27.5-29.9 (RR = 1.26, 95% CI: 1.03, 1.53), 30.0-32.4 (RR = 1.37, 95% CI: 1.09, 1.72), and > or =32.5 (RR = 1.23, 95% CI: 0.96, 1.59). These prospective data support the hypothesis that obesity increases the risk of colon cancer death and that the relation is stronger and more linear in men than in women.     

Association of obesity and cancer risk in Canada

The authors conducted a population-based, case-control study of 21,022 incident cases of 19 types of cancer and 5,039 controls aged 20-76 years during 1994-1997 to examine the association between obesity and the risks of various cancers. Compared with people with a body mass index of less than 25 kg/m(2), obese (body mass index of > or = 30 kg/m(2)) men and women had an increased risk of overall cancer (multivariable adjusted odds ratio = 1.34, 95% confidence interval (CI): 1.22, 1.48), non-Hodgkin's lymphoma (odds ratio = 1.46, 95% CI: 1.24, 1.72), leukemia (odds ratio = 1.61, 95% CI: 1.32, 1.96), multiple myeloma (odds ratio = 2.06, 95% CI: 1.46, 2.89), and cancers of the kidney (odds ratio = 2.74, 95% CI: 2.30, 3.25), colon (odds ratio = 1.93, 95% CI: 1.61, 2.31), rectum (odds ratio = 1.65, 95% CI: 1.36, 2.00), pancreas (odds ratio = 1.51, 95% CI: 1.19, 1.92), breast (in postmenopausal women) (odds ratio = 1.66, 95% CI: 1.33, 2.06), ovary (odds ratio = 1.95, 95% CI: 1.44, 2.64), and prostate (odds ratio = 1.27, 95% CI: 1.09, 1.47). Overall, excess body mass accounted for 7.7% of all cancers in Canada-9.7% in men and 5.9% in women. This study provides further evidence that obesity increases the risk of overall cancer, non-Hodgkin's lymphoma, leukemia, multiple myeloma, and cancers of the kidney, colon, rectum, breast (in postmenopausal women), pancreas, ovary, and prostate.     

Daily total physical activity level and total cancer risk in men and women: results from a large-scale population-based cohort study in Japan

The impact of total physical activity level on cancer risk has not been fully clarified, particularly in non-Western, relatively lean populations. The authors prospectively examined the association between daily total physical activity (using a metabolic equivalents/day score) and subsequent cancer risk in the Japan Public Health Center-based Prospective Study. A total of 79,771 general-population Japanese men and women aged 45-74 years who responded to a questionnaire in 1995-1999 were followed for total cancer incidence (4,334 cases) through 2004. Compared with subjects in the lowest quartile, increased daily physical activity was associated with a significantly decreased risk of cancer in both sexes. In men, hazard ratios for the second, third, and highest quartiles were 1.00 (95% confidence interval (CI): 0.90, 1.11), 0.96 (95% CI: 0.86, 1.07), and 0.87 (95% CI: 0.78, 0.96), respectively (p for trend = 0.005); in women, hazard ratios were 0.93 (95% CI: 0.82, 1.05), 0.84 (95% CI: 0.73, 0.96), and 0.84 (95% CI: 0.73, 0.97), respectively (p for trend = 0.007). The decreased risk was more clearly observed in women than in men, especially among the elderly and those who regularly engaged in leisure-time sports or physical exercise. By site, decreased risks were observed for cancers of the colon, liver, and pancreas in men and for cancer of the stomach in women. Increased daily physical activity may be beneficial in preventing cancer in a relatively lean population.     

Trans-fatty acids and colon cancer.

Trans-fatty acids have been hypothesized to be carcinogenic, although there are limited data in humans testing this hypothesis. In this study, we examine the association between trans-fatty acids and colon cancer using data from a case (n = 1,993)-control (n = 2,410) study conducted in Utah, Northern California, and Minnesota. Dietary data were collected using a detailed diet history questionnaire, and nutrient values were generated from the Nutrition Coordinating Center nutrient database. After adjustment for other variables, including age at diagnosis, body size, physical activity, aspirin and/or nonsteroidal anti-inflammatory drug (referred to collectively as NSAIDs) use, energy intake, and dietary fiber and calcium, we found a weak association in women [odds ratio (OR) = 1.5, 95% confidence interval (CI) = 1.1-2.0] but not in men (OR = 1.2, 95% CI = 0.9-1.7); no increased risk was observed for the cis form of the fatty acids. For men and women, slightly stronger associations were observed in those > or = 67 years of age (OR = 1.4, 95% CI = 0.9-2.1 for men; OR = 1.6, 95% CI = 1.0-2.4 for women). Those who did not use NSAIDs were at a 50% greater risk of developing colon cancer when they consumed high levels of trans-fatty acids. Women who were estrogen negative, i.e., postmenopausal not taking hormone replace therapy, had a twofold increase in risk from high levels of trans-fatty acids in the diet, while women who were estrogen positive did not experience an increased risk of colon cancer, regardless of level of trans-fatty acids consumed. We believe that these data have important public health implications. It seems prudent to avoid consuming partially hydrogenated fats, since no increased risk was observed for the cis form of fatty acids, while suggestions of increased risk from trans-fatty acids exist for subsets of the population.     

Factors associated with low bone mineral density among white women

OBJECTIVE: To analyze whether the factors causing low bone mineral density among elderly women are the same as those observed in other age groups. METHODS: A cross-sectional study was carried out on the medical records of a random sample of 413 white women seen at an imaging diagnostics service in a city of Southern Brazil, in 2003. Femoral bone mineral densities with adjustment using T-scores were used. The following variables were investigated: age, body mass index, tobacco smoking, alcohol consumption, milk consumption, physical activity and hormone replacement therapy. Univariate and multivariate unconditional logistic regression were used. RESULTS: In the sample, 52.5% were up to 59 years old and 47.5% were 60 or over. The mean bone mineral density was 0.867 g/cm2 (SD=0.151) for the femoral neck. Significant age-adjusted values were obtained for physical activity (adjusted OR=0.47; 95% CI: 0.23;0.97), body mass index greater than or equal to 30.0 kg/m2 (adjusted OR=0.10; 95% CI: 0.05;0.21), alcohol consumption (adjusted OR=7.90; 95% CI: 2.17;28.75), low milk consumption (adjusted OR=3.29; 95% CI: 1.91;5.68) and hormone replacement (adjusted OR = 0.44; 95% CI: 0.21;0.90). Among the elderly women, body mass, milk consumption and physical activity were independent protection factors. CONCLUSIONS: Advanced age, body mass, physical activity, milk and alcohol consumption were important factors in bone mass regulation. The influence of behavioral factors was maintained among the women of advanced aged, thus reinforcing the role of preventive measures in medical practice and public health promotion policies aimed at healthy aging.     

Body weight dissatisfaction by socioeconomic status among obese, preobese and normal weight women and men: results of the cross-sectional KORA Augsburg S4 population survey

ABSTRACT: BACKGROUND: Body weight dissatisfaction is an important factor in preventing weight gain and promoting weight loss or maintenance. This study focuses on differences in the rates of body weight dissatisfaction among obese, preobese and normal weight women and men by socioeconomic status within a general adult population in Germany. METHODS: Data were analyzed from 4186 adults aged 25 to 74 who participated in a cross-sectional, representative population-based health survey (KORA S4, 1999-2001, Augsburg region/Germany). Body mass was measured anthropometrically and indexed following international standards. Among the 2123 women participating in the survey, 40.3% had a normal weight, 34.9% were preobese, and 24.8% were obese (compared to 25.9%, 51.4% and 22.6% among men, respectively). Body weight dissatisfaction, educational level, household income and occupational status were assessed by computer-aided personal interviewing. An index for socioeconomic status was calculated and categorized into quintiles. Multiple logistic regressions were performed to test for differences in the odds of body weight dissatisfaction across socioeconomic strata in normal weight, preobese and obese groups. Body mass index, age, family status, place of residence and health behaviors were adjusted for. RESULTS: Overall, being dissatisfied with one's body weight was more prevalent in women (48.3%) than in men (33.2%). In the normal weight group, no significant differences in the odds of being dissatisfied were found across socioeconomic groups among women or men. Among preobese men, compared to the lowest socioeconomic stratum, increased odds of being dissatisfied with one's body weight were associated with the highest socioeconomic index group (OR=2.3, 95% CI: 1.4-3.8), middle and high educational level (OR=1.6, 95% CI: 1.1-2.3, and OR=1.9, 95% CI: 1.3-3.7), high income (OR=1.8, 95% CI: 1.2-2.7), and middle and high occupational status (both OR=1.8, 95% CI: 1.2-2.6). Among preobese women, the odds of being dissatisfied were only significantly elevated in those with a middle educational level (OR=1.6, 95% CI: 1.1-2.3). Among obese men, elevated odds were found in the highest socioeconomic index group (OR=3.7, 95% CI: 1.8-7.5) and in those with a high educational level (OR=2.3, 95% CI: 1.3-4.1), high income (OR=2.6, 95% CI: 1.4-4.7), and middle and high occupational status (both OR=2.2, 95% CI: 1.3-3.6). The odds of dissatisfaction among obese women were not associated with socioeconomic status as a whole, but were associated with a high educational level, albeit with a comparatively large confidence interval (OR=3.6, 95% CI: 1.0-12.8). CONCLUSIONS: In Germany, body weight dissatisfaction is more prevalent among obese and preobese men in high socioeconomic status groups, a pattern not found in women. The exception to this is a greater prevalence of dissatisfaction among obese and preobese women with a high educational level (albeit inconsistently). Moreover, there is a social gradient in body weight dissatisfaction, especially in obese men, which may partly explain why obesity is more prevalent in men with low socioeconomic status. It also suggests that they are a target group for obesity care in which body weight satisfaction is an important topic.     

Physical activity and breast cancer risk among women in the southwestern United States

Physical activity may influence breast cancer risk through multiple mechanisms and at different periods in life. In this study we evaluate breast cancer risk associated with total and vigorous physical activity at ages 15, 30, and 50 years and the referent year prior to diagnosis/selection. Participants were non-Hispanic white (NHW) (1527 cases and 1601 control subjects) and Hispanic/American Indian (HAI) (798 cases and 924 controls) women. Both total and vigorous activity reduced risk of breast cancer in a dose-response manner. Among premenopausal women, only high total metabolic equivalent of the task (MET) hours of activity during the referent year was associated with reduced breast cancer risk in NHW women (odds ratio [OR] 0.62; 95% confidence interval [CI] 0.43, 0.91). Among postmenopausal women, physical activity had the greatest influence among women not recently exposed to hormones. Among these women, high total lifetime activity reduced risk of breast cancer for both NHW (OR 0.60; 95% CI 0.36, 1.02; p trend 0.01) and HAI women (OR 0.52; 95% CI 0.23, 1.16; p trend 0.07). Additionally, high total MET hours of activity at age 30 years (OR 0.56; 95% CI 0.37, 0.85) and at age 15 years (OR 0.57; 95% CI 0.38, 0.88) reduced breast cancer risk among postmenopausal NHW women not recently exposed to hormones. Among HAI women, more recent activity performed during the referent year and at age 50 appeared to have the greatest influence on breast cancer risk. Among postmenopausal NHW women. there was a significant interaction between physical activity and hormone replacement therapy (p value, 0.01), while among postmenopausal HAI women, physical activity interacted with body mass index (p value, 0.04). These data suggest that physical activity is important in reducing risk of breast cancer in both NHW and HAI women.