Physical exercise, body mass index, and risk of chronic pain in the low back and neck/shoulders: longitudinal data from the Nord-Trondelag Health Study

Chronic musculoskeletal pain constitutes a large socioeconomic challenge, and preventive measures with documented effects are warranted. The authors' aim in this study was to prospectively investigate the association between physical exercise, body mass index (BMI), and risk of chronic pain in the low back and neck/shoulders. The study comprised data on approximately 30,000 women and men in the Nord-Tr?ndelag Health Study (Norway) who reported no pain or physical impairment at baseline in 1984-1986. Occurrence of chronic musculoskeletal pain was assessed at follow-up in 1995-1997. A generalized linear model was used to calculate adjusted risk ratios. For both females and males, hours of physical exercise per week were linearly and inversely associated with risk of chronic pain in the low back (women: P-trend = 0.02; men: P-trend < 0.001) and neck/shoulders (women: P-trend = 0.002; men: P-trend < 0.001). Obese women and men had an approximately 20% increased risk of chronic pain in both the low back and the neck/shoulders. Exercising for 1 or more hours per week compensated, to some extent, for the adverse effect of high BMI on risk of chronic pain. The authors conclude that physical inactivity and high BMI are associated with an increased risk of chronic pain in the low back and neck/shoulders in the general adult population.     

Body mass index and cardiovascular mortality at different levels of blood pressure: a prospective study of Norwegian men and women.

STUDY OBJECTIVE--The study investigated the joint effect of body mass index and systolic blood pressure on cardiovascular and total mortality. DESIGN--This was a prospective cohort study. The main outcome measures were age adjusted mortality and relative risks estimated from survival models. SETTING--The population of the city of Bergen, Norway. PARTICIPANTS--Subjects were 21,145 men and 30,330 women aged 30-79 years at the time of examination in 1963. MAIN RESULTS--Both cause specific and all cause mortality increased with systolic blood pressure within each category of body mass index. Stroke mortality was not significantly associated with body mass index when adjusted for systolic blood pressure in either age group of men or women. Coronary heart disease mortality increased on average 30% per 5 kg/m2 increase in body mass index in men and women aged 30-59 years at baseline. Adjusted for systolic blood pressure, the relative risks were reduced to 1.20 (95% confidence interval (CI) 1.12, 1.29) in men and 1.10 (95% CI 1.03, 1.18) in women. They were similar at each level of systolic blood pressure. For coronary heart disease mortality in men and women aged 60-79 years at measurement a negative interaction between body mass index and systolic blood pressure was suggested in the first five years. Excluding the first five years, adjusted relative risks per 5 kg/m2, were 1.05 (95% CI 0.96, 1.15) in men and 1.11 (95% CI 1.04, 1.17) in women in the older age group. There was an upturn in cardiovascular mortality at low levels of body mass index in both age groups of women, but not in men. CONCLUSIONS--Hypertension is an important risk factor for cardiovascular and all cause mortality even in the obese. Body mass index is generally a weak predictor of cardiovascular mortality in this population. It is a stronger risk factor of coronary death in men when measured at a younger age. Thin people with hypertension are not at particularly high risk of death from coronary heart disease compared with their obese counterparts, except possibly in the first few years after measurement in the elderly. Being underweight is associated with increased risk of death from all cardiovascular causes in women, but not in men.     

Relation of height, body mass, energy intake, and physical activity to risk of renal cell carcinoma: results from the Netherlands Cohort Study

Data from the Netherlands Cohort Study on Diet and Cancer were used to investigate the association between anthropometry, energy intake, and physical activity and risk of renal cell carcinoma (RCC). The Netherlands Cohort Study on Diet and Cancer consists of 120,852 men and women aged 55-69 years who completed a self-administered questionnaire at baseline (1986). A case-cohort approach was used. After 9.3 years of follow-up, 275 microscopically confirmed incident cases were available for analysis. Incidence rate ratios for RCC were estimated using Cox proportional hazards models. Height was associated with RCC risk only in women (per 5-cm increment, rate ratio (RR) = 1.23, 95% confidence interval (CI): 1.03, 1.46). Body mass index (weight (kg)/height (m)(2)) was associated with increased risk of RCC (per 1-kg/m(2 )increment, RR = 1.07, 95% CI: 1.02, 1.12) for men and women, as was gain in body mass index from age 20 years to baseline (per 1-kg/m(2 )increment, RR = 1.06, 95% CI: 1.01, 1.10). Energy intake was not related to RCC risk, while a possible protective effect was observed for physical activity in men. These results suggest that body mass index and gain in body mass index since age 20 are associated with increased risk of RCC.     

Relationships between obesity and DSM-IV major depressive disorder, suicide ideation, and suicide attempts: results from a general population study

OBJECTIVES: This study sought to test the relationships between relative body weight and clinical depression, suicide ideation, and suicide attempts in an adult US general population sample. METHODS: Respondents were 40,086 African American and White participants interviewed in a national survey. Outcome measures were past-year major depression, suicide ideation, and suicide attempts diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. The primary predictor was relative body weight, treated both continuously (i.e., body mass index [BMI]) and categorically in logistic regression analyses. Covariates included age, income and education, disease status, and drug and alcohol use. RESULTS: Relative body weight was associated with major depression, suicide attempts, and suicide ideation, although relationships were different for men and women. Among women, increased BMI was associated with both major depression and suicide ideation. Among men, lower BMI was associated with major depression, suicide attempts, and suicide ideation. There were no racial differences. CONCLUSIONS: Differences in BMI, or weight status, were associated with the probability of past-year major depression, suicide attempts, and suicide ideation. Longitudinal studies are needed to differentiate the causal pathways and mechanisms linking physical and psychiatric conditions.     

Role of anxiety and depression in the onset of spontaneous preterm labor

The aim of this cohort study conducted in France in 1997-1998 was to investigate the effects of antenatal anxiety and depression on spontaneous preterm labor. A consecutive series of 634 pregnant women with singleton pregnancies was included. Anxiety and depression were assessed using self-administered questionnaires: Spielberger's State-Trait Anxiety Inventory and the Edinburgh depression scale. Depression scores were dichotomized with a cutoff value suggestive of major depression. The 75th percentile was used for anxiety scores. A logistic regression analysis, controlling for sociodemographic and biomedical factors and including interaction terms, revealed that depression was positively associated with the outcome among underweight women, defined as women with a prepregnancy body mass index below 19 (adjusted odds ratio (OR) = 6.9, 95% confidence interval (CI): 1.8, 26.2). A similar result was observed for trait anxiety in women with a history of preterm labor (adjusted OR = 4.8, 95% CI: 1.1, 20.4). The association was close to significance for state anxiety in women with vaginal bleeding (adjusted OR = 3.6, 95% CI: 0.9, 14.7). These findings show that anxiety and depression, when combined with specific biomedical factors, are associated with spontaneous preterm labor. A synergic action of psychological and biomedical factors on the secretion of placental corticotropin-releasing factor is hypothesized.     

Trends in coronary risk factors in Italy. Responsible Investigators of the RF2, OB43 and MICOL Research Groups.

Three large-scale epidemiological surveys covering some major coronary risk factors were conducted in Italy in population samples of men and women aged 30-59 years. The first survey was carried out in 1978-1979 (RF2 study; nine samples in eight regions; 2561 men and 2912 women); the second in 1983-1984 (OB43 study; nine samples in the same eight regions; 2267 men and 2398 women); and the third one in 1985-1987 (MICOL study; 18 samples in 10 regions; 14,411 men and 12,611 women). Time trends in mean age standardized risk factors levels showed slight but systematic decreases in blood pressure, cigarette smoking (only in men), and body mass index (only in women); whereas no substantial changes were observed in serum cholesterol levels. The combined multiple coronary risk estimated by a model produced in a previous study, showed a decline between 1978-1979 and 1983-1984 of 5.5% in men and 13.4% in women. These changes were compared with the official coronary death rates between 1984 and 1987 in the whole country and in the regions where the samples were located. The expected/observed ratio computed in different ways ranged from 0.54 to 0.88 for men and was over 1 for women. Changes in the levels of major risk factors and changes in coronary mortality seem biologically coherent at least in men.     

Ghrelin, adiponectin, and leptin do not predict long-term changes in weight and body mass index in older adults: longitudinal analysis of the Rancho Bernardo cohort

Ghrelin, leptin, and adiponectin are associated with body size in cross-sectional studies; it is unknown whether these hormones predict long-term changes in body size. Multilevel models were used to study associations between fasting serum hormones, measured in 698 men and 619 women (60-91 years) in samples collected at baseline (1984-1987), and changes in weight and body mass index, assessed repeatedly over a follow-up period of up to 18 years (median, 4.7 years). Baseline weight was -1.5 kg lower for a one-standard-deviation increment in ghrelin and -3.3 kg lower for a one-standard-deviation increment in adiponectin, similar in men and women. For leptin, baseline weight was 12.1 kg higher for a one-standard-deviation increment in men, compared with 5.7 kg in women (sex-interaction p < or = 0.0001). Ghrelin and adiponectin did not affect weight change; their associations with weight were constant over time, indicated by nonsignificant hormone-by-time interactions. The positive association between leptin and weight became slightly weaker over time. Results were similar when investigating repeated measures of body mass index. From this analysis of Rancho Bernardo Study data, the authors conclude that ghrelin, adiponectin, and leptin do not predict weight gain beyond reflecting the influence of attained body size on future changes in weight or body mass index.     

Body mass index versus height and weight in relation to blood pressure. Findings for the 10,079 persons in the INTERSALT Study

In INTERSALT, an international study of electrolytes and blood pressure, body mass index (kg/m2) was found to relate independently to blood pressure. These relations were assessed in 10,079 men and women aged 20-59 years from 52 centers around the world, based on a standardized protocol, central training of observers, a central laboratory, and extensive quality control. The purpose of the present analyses was to determine whether weight, directly adjusted for height, related to blood pressure as strongly as did body mass index. For all men and women combined, with adjustment for age, sex, alcohol intake, smoking, and sodium and potassium excretion in addition to height, the partial correlations of blood pressure with weight were 0.221 for systolic blood pressure and 0.238 for diastolic blood pressure. These values were slightly larger than the partial correlations for body mass index with blood pressure, which were 0.215 and 0.229, respectively. Although the regression coefficients for body mass index with systolic pressure had been larger in men than in women, suggesting a stronger association of systolic pressure with weight in men, the models with weight directly adjusted for height indicated that the difference in systolic pressure associated with a 10-kg difference in weight was 3.0 mmHg in both men and women. The corresponding weight-associated diastolic pressure differences ranged from 2.00 mmHg in women aged 40-59 years to 2.7 mmHg in men aged 20-39. In addition, with control for weight, height had a significant inverse association with blood pressure. The results of these analyses support the use of weight, with direct adjustment for height, as a useful and practical substitute for body mass index in analyses of the association of adiposity with blood pressure.     

Prepregnancy body mass index, vaginal inflammation, and the racial disparity in preterm birth

The authors sought to quantify the overall and race/ethnic-specific relations between prepregnancy body mass index and both preterm birth and vaginal inflammation. Data from a cohort of 11,392 women who enrolled in the multicenter Vaginal Infections and Prematurity Study (1984-1989) at 23-26 weeks' gestation were used. Compared with a prepregnancy body mass index of 22, a body mass index of 16 increased the risk of preterm birth by 90% (odds ratio = 1.9, 95% confidence interval (CI): 1.5, 2.6), and a body mass index of 18 increased the risk by 40% (odds ratio = 1.4, 95% CI: 1.2, 1.7). Ethnicity substantially modified the magnitude of the body mass index effect and the shape of the preterm birth risk curve, with underweight having a greater impact on preterm birth among Blacks and Hispanics than among Whites. Low body mass index increased the risk of a high level of neutrophils (> 5 per oil immersion field) and a high vaginal pH measurement (> or = 5.0) among Black women; for a body mass index of 16 versus 22, the odds ratio = 1.7 (95% CI: 1.1, 2.6). Compared with Black women with a body mass index of 22, Blacks with a body mass index of 16 had a 1.7-fold increased risk for a high level of neutrophils and a high vaginal pH measurement, while those with a body mass index of 18 had a 1.3-fold increased risk.     

Association of visceral adipose tissue with incident myocardial infarction in older men and women: the Health, Aging and Body Composition Study

Assessment of body fat distribution, particularly visceral adipose tissue, may be important for accurate risk evaluation for cardiovascular disease in the elderly. This 1997-1998 US study examined the association of incident myocardial infarction (MI) with total adiposity (body mass index and fat mass) and body fat distribution (waist-to-thigh ratio, waist circumference, visceral and subcutaneous adipose tissue) in well-functioning men (n = 1,116) and women (n = 1,387) aged 70-79 years enrolled in the Health, Aging and Body Composition Study. There were 116 MI events (71 in men, 45 in women) during an average follow-up time of 4.6 (standard deviation, 0.9) years. No association was found between incident MI and the adiposity or fat distribution variables for men. For women, visceral adipose tissue was an independent predictor of MI (hazard ratio = 1.67, 95% confidence interval: 1.28, 2.17 per standard-deviation increase; p < 0.001). No association was found between body mass index or total fat mass and MI events in women. The association of visceral adipose tissue with MI in women was independent of high density lipoprotein cholesterol, interleukin-6 concentration, hypertension, and diabetes (hazard ratio = 1.79, 95% confidence interval: 1.24, 2.58 per standard-deviation increase; p < 0.01). The amount of adipose tissue stored in the intraabdominal cavity is an important, independent risk factor for MI in well-functioning, elderly women.     

Body mass index in relation to adult asthma among 135,000 Norwegian men and women

The authors estimated the association between asthma and body mass index in a 1963-2002 study of 135,000 Norwegians aged 14-60 years who were followed on average for 21 years. Cox proportional hazards regression models were fitted to estimate the relative risk of asthma adjusting for smoking, education, and physical activity. Compared with persons with a body mass index (weight (kg)/height (m)(2)) of less than 25, overweight (body mass index: 25-29) men and women had relative risks of asthma of 1.27 (95% confidence interval (CI): 1.13, 1.43) and 1.30 (95% CI: 1.17, 1.45), respectively, while obese (body mass index: >/=30) men and women had relative risks of 1.78 (95% CI: 1.35, 2.34) and 1.99 (95% CI: 1.67, 2.37), respectively. Stratified analyses revealed a similar association between body mass index and asthma for never smokers, ever smokers, persons with less than or equal to 12 years of education, and persons with more than 12 years of education. Analyses including all the covariates gave results similar to those not adjusting for these factors. The risk of asthma increased steadily with body mass index, from a body mass index of 20 in men and of 22 in women. In men, the risk of asthma increased by 10% with each unit of increased body mass index between 25 and 30. The similar value for women was 7%. Overweight or obese persons reported asthma more often than did thinner persons after adjustment for smoking, education, and physical activity.     

Dietary fat,calories, and the risk of breast cancer in postmenopausal women: a prospective population-based study.

We tested the hypothesis that a high-fat diet increases the risk of breast cancer in a population-based study of 590 women aged 40-79 years who were without known breast cancer when they provided a quantitative 24-hour diet recall. Fifteen postmenopausal women were diagnosed with incident breast cancer during the next 15 years (approximately 7600 person-years of follow-up). These women had significantly higher age-adjusted intake of all fats (monounsaturated, polyunsaturated, and saturated), and oleic, linoleic, and linolenic acids, with a stepwise increase in risk across tertiles of intake. Fat intake was associated with total calories, protein, and carbohydrates, and women with incident breast cancer consumed more calories, protein, and carbohydrates than did other subjects. When each nutrient variable (calories, fats, protein, and carbohydrates) was adjusted for age, body mass index, age at menopause, parity, and alcohol consumption, the strongest risks for incident breast cancer were associated with total calories (relative risk per standard deviation = 2.72, 95% confidence interval = 1.51-4.89, p = 0.002) and total fats (relative risk per standard deviation = 2.01, 95% confidence interval = 1.19-3.41, p = 0.01). Fat composition of the diet, expressed either as percent of energy or as fat intake adjusted for calories by regression analysis, was not significantly associated with risk of breast cancer. These results support the hypothesis that total calorie consumption, as well as dietary fat consumption, is a risk factor for breast cancer in postmenopausal women, and parallel observations in animal models.     

Obesity and the risk of Parkinson's disease

Dopamine is involved in the regulation of food intake, and obese persons have decreased dopamine D2 receptor availability in the striatum. Furthermore, midlife triceps skinfold thickness has been found to be positively associated with the risk of Parkinson's disease (PD) among Japanese-American men in Hawaii. The authors prospectively investigated whether obesity was associated with PD risk in two large cohorts of US men and women. They documented 249 cases of PD in men (1986-2000) and 202 cases in women (1976-1998). Neither baseline body mass index (weight (kg)/height (m)(2)) nor early adult body mass index was associated with PD risk. The multivariate relative risk for a baseline body mass index of > or = 30 versus <23 was 0.8 (95% confidence interval (CI): 0.6, 1.2; p for trend = 0.3). Overall, waist circumference and waist-to-hip ratio were not related to PD risk. However, among never smokers, both variables showed significantly positive associations with PD risk. The relative risks for comparisons of extreme quintiles were 1.9 (95% CI: 1.0, 3.4; p for trend = 0.03) for waist circumference and 2.0 (95% CI: 1.1, 3.6; p for trend = 0.03) for waist-to-hip ratio. The results do not support a role of overall obesity in PD pathogenesis; however, central obesity may be associated with higher PD risk among never smokers, and this finding merits further investigation.     

A prospective study of folate intake and the risk of pancreatic cancer in men and women

Laboratory and human studies suggest that folate intake may influence the risk of some cancers. However, prospective information about the relation between folate intake and the risk of exocrine pancreatic cancer is limited. The authors examined the relation of dietary folate intake to the risk of pancreatic cancer in two large prospective US cohorts. Folate intake was assessed by food frequency questionnaire in 1984 in women and in 1986 in men. Multivariate relative risks were adjusted for age, energy intake, cigarette smoking, body mass index, diabetes, and height. During 14 years' follow-up in each cohort, 326 incident cases of pancreatic cancer were identified. Compared with participants in the lowest category of folate intake, participants in increasing 100- micro g categories of total energy-adjusted folate intake had pooled multivariate relative risks for pancreatic cancer of 1.08, 1.10, and 1.03 (95% confidence interval: 0.74, 1.43; p(trend) = 0.99). For energy-adjusted folate from food, the pooled relative risks for increasing 100- micro g categories of intake were 0.81, 0.89, and 0.66 (95% confidence interval: 0.42, 1.03; p(trend) = 0.12). There was no statistical interaction between folate intake and methionine, alcohol, fat, or caffeine. The results from these two large prospective cohorts do not support a strong association between energy-adjusted folate intake and the risk of pancreatic cancer.     

Gender differences in risk factors for attempted suicide among young adults: findings from the Third National Health and Nutrition Examination Survey

PURPOSE: To identify the significant factors associated with attempted suicide among men and women, and determine whether socioeconomic status (SES) and social support indictors, health risk factors, and lifetime history of medical and psychiatric illnesses can explain gender differences in attempted suicide. METHODS: We used data from 3357 men and 4004 women aged 17 to 39 years, who completed a mental disorder diagnostic interview as a part of the Third National Health and Nutrition Examination Survey, 1988-1994. Adjusted odds ratios (ORs) were calculated for the association between risk factors and attempted suicide. RESULTS: The prevalence of lifetime attempted suicides was 7.58% (SE, 0.66) in women and 3.69% (SE, 0.49) in men. In men, low income and smoking were associated with attempted suicide, while attempted suicide in women was associated with poor self-evaluated health, low educational attainment, and drug use. A history of medical and psychiatric illnesses was associated with attempted suicide in both genders, for cancer/pulmonary disease, OR=2.89 (95% CI, 1.25-6.67) in men and 1.94 (1.09-3.45) in women; for major depressive disorder, OR=9.86 (5.08-19.14) in men and 5.00 (3.19-7.83) in women. The significant gender difference of attempted suicide prevalence remained after being adjusted for risk factors selected. CONCLUSION: There were significant gender differences in the risk factors for attempted suicide among young adults, and the gender difference in the prevalence of lifetime attempted suicides could not be explained by differential exposure to risk factors selected.     

Effect of cardiorespiratory fitness on mortality among hypertensive and normotensive women and men

BACKGROUND: The effects of fitness on mortality either from cardiovascular disease (CVD) or from all causes, among hypertensive adults, are not fully understood, especially among women. The objective of this study was to examine the effect of fitness on all-cause and CVD mortality among hypertensive and normotensive women and men. METHODS: Using the Lipids Research Clinics Prevalence Study, we examined the relationship of fitness with mortality among 2712 women and 3000 men followed from 1972-1976 to 1998. Cardiorespiratory fitness was measured using a treadmill test. Sex-specific hazard ratios (HRs) were calculated from proportional hazard models of fitness predicting all-cause or CVD mortality, adjusted for age, education, race, smoking, alcohol, body mass index, and hyperlipidemic sampling strata. RESULTS: Comparing the lowest with the highest quintile of fitness, the adjusted all-cause mortality among hypertensive women was 1.7 (95% confidence interval = 0.9-3.2) and among normotensive women was 2.3 (1.5-3.7). Comparing the same quintiles of fitness, the adjusted all-cause mortality among hypertensive men was 2.0 (1.2-3.4), and among normotensive men it was 1.9 (1.3-2.7). Elevated risks were also observed for CVD mortality. CONCLUSION: Higher levels of fitness were associated with a lower risk of all-cause and CVD mortality among both hypertensive and normotensive women and men.     

Trends in selected biological risk factors for cardiovascular diseases in the Danish MONICA population, 1982-1992

Data from 6695 men and women of ages 30, 40, 50, and 60 years, examined in the Danish WHO MONICA surveys in 1982-84, in 1986-87, and in 1991-92, were analyzed to estimate secular trends in body height and weight, blood pressure, and serum total, HDL-, and LDL-cholesterol, and triglyceride. Body height increased 0.1% per year, and body mass index increased 0.4% per year in women. Diastolic blood pressure increased 0.4% per year in women and 0.6% per year in 60-year-old men. HDL cholesterol declined 0.4% per year. Body mass indices in men, diastolic blood pressures in men <60 years of age, systolic blood pressures, total- and LDL cholesterol and triglyceride did not change. The levels of biological risk factors in the Danish WHO MONICA study population did not show trends during the 1980s that help explain the declining incidence of myocardial infarction in the population.     

Increase in body fatness as a major determinant of changes in serum total cholesterol and high density lipoprotein cholesterol in young men over a 10-year period

Serum cholesterol rises with age in most Western (and Westernized) populations. To identify causes of this rise, the authors studied 315 young Dutch men in 1976 in the district of Utrecht, The Netherlands, when they were aged 18 or 19 years, and again in various towns in the same region 10 years later, in 1986. These men formed the lower and upper quartiles of the distribution of changes in body mass index (weight (kg)/height (m)2) from 1976 to 1986 in a larger cohort of men representative of all Dutch men aged 18 or 19 years in 1976. In 10 years, mean serum total cholesterol (+/- standard deviation) had increased by 1.20 +/- 0.88 mmol/liter (46 +/- 34 mg/100 ml), and high density lipoprotein (HDL) cholesterol had decreased by 0.12 +/- 0.21 mmol/liter (4.6 +/- 8.1 mg/100 ml). The mean increase in body mass index was 2.7 +/- 2.5 kg/m2, and the mean increase in body fat percentage (assessed from skinfolds) was 3.3 +/- 4.6 g/100 g. The mean subscapular:tricipital skinfold thickness ratio--an indicator of body fat distribution--had not changed. In multiple regression analysis, the change in body mass index was the only significant (p less than 0.001) determinant of changes in serum total cholesterol; an increase of 1 kg/m2 in body mass index was associated with an increase of 0.20 mmol/liter (standard error, 0.02) in serum total cholesterol. Changes in body mass index and in smoking habits both contributed significantly toward explanation of changes in HDL cholesterol and in the HDL cholesterol:total cholesterol ratio. If smoking habits were adjusted for, HDL cholesterol decreased by 0.02 mmol/liter and the HDL cholesterol:total cholesterol ratio decreased by 0.012 (standard error, 0.001) for every 1 kg/m2 increase in body mass index. Changes in body fat distribution, as assessed by skinfold ratio, were not associated with changes in lipids. By interpolation, the authors estimated that for the full cohort of men, including the second and third quartile of body mass index changes, the mean rise in cholesterol had been 1.15 mmol/liter (44 mg/100 ml), of which 0.47 mmol/liter could be explained by the estimated rise in body mass index of 2.4 kg/m2. An increase in body fatness between ages 19 and 29 years is a powerful determinant of the rise in total cholesterol and the fall in HDL cholesterol occurring over that period of time.     

Physical activity and breast cancer risk in hispanic and non-hispanic white women

To investigate breast cancer risk in Hispanic and non-Hispanic White women, the authors conducted a population-based case-control study of New Mexican women during 1992-1994 using incident breast cancer cases aged 35-74 years and frequency-matched controls selected using random digit dialing. Activity type and weekly duration of usual nonoccupational physical activity were used to calculate weekly metabolic equivalent (MET)-hours of total and vigorous physical activity (> or =5 METs). Conditional logistic regression models were fitted to estimate the relative risk of breast cancer for levels of physical activity and to assess the difference in effects by ethnicity, body mass index, energy intake, and menopausal status. Vigorous physical activity was associated with reduced breast cancer risk in both Hispanic and non-Hispanic White women. Women in the highest category of vigorous activity had lower risk of breast cancer (adjusted odds ratio = 0.34, 95% confidence interval: 0.22, 0.51 for Hispanic; adjusted odds ratio = 0.60, 95% confidence interval: 0.41, 0.89 for non-Hispanic White women) compared with women reporting no vigorous physical activity. Both pre- and postmenopausal Hispanic women showed decreasing risk with increasing level of activity. Physical activity was protective only among postmenopausal non-Hispanic White women. The effects of physical activity were independent from reproductive factors, usual body mass index, body mass index at age 18, adult weight gain, and total energy intake.     

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.