Obesity and risk of nonfatal unintentional injuries

BACKGROUND: Obesity is recognized as a risk factor for multiple chronic diseases. Yet, it is unclear whether obesity is also associated with an increased risk of nonfatal unintentional injury. METHODS: A population-based survey was conducted among adults aged > or = 18 years from January 1999 through October 2000. The relationship was investigated between body mass index (BMI), defined as weight in kilograms divided by the square of the height in meters (kg/m2), and risk of nonfatal unintentional injuries among 2575 respondents aged > or = 20 years by comparing percentage of adults between obese and nonobese respondents who had injuries. Multivariate logistic regression further examined this relationship by controlling for confounding demographics. RESULTS: A total of 370 respondents reported injuries in the previous year. We observed a linear dose-response trend among women. An estimated 7.0% of underweight individuals (BMI <18.5) reported injuries. In contrast, 26.0% of men and 21.7% of women with a BMI > or = 35.0 reported injuries. The odds ratio of injuries for individuals with a BMI > or = 35.0 was 2.00 (95% confidence interval=1.07-3.74, p<0.05) after controlling for gender, age, education level, marital status, family poverty status, and area of residence. CONCLUSIONS: A marginally significant association between extreme obesity and elevated risk of injuries was observed. Efforts to promote optimal body weight may reduce not only the risk of chronic diseases but also the risk of unintentional injury among overweight and obese individuals.     

Overweight, obesity, and binge eating in a non-clinical sample of five Brazilian cities

OBJECTIVE: To investigate the relationship between obesity/overweight and binge eating episodes (BEEs) in a large nonclinical population. RESEARCH METHODS AND PROCEDURES: Consumers at shopping centers in five Brazilian cities (N = 2858) who participated in an overweight prevention program were interviewed and had weight and height measured to calculate BMI. RESULTS: Prevalence of overweight (BMI = 25 to 29.9 kg/m2) was 46.6% for men and 36.6% for women. Obesity (BMI > or = 30 kg/m2) was about two-thirds of the prevalence of overweight. BEEs (subjects who binged one or more times per week over the last 3 months) in normal-weight individuals was 1.4% for men and 3.9% for women, whereas in overweight/obese, these prevalences were 6.5% and 5.5%, respectively (p < 0.01). After adjustment for age, socioeconomic variables, and childhood obesity, those who reported BEEs had an odds ratio of being overweight/obese of 3.31 (95% confidence interval: 1.11 to 9.85) for men and 1.73 (95% confidence interval: 1.05 to 2.84) for women. DISCUSSION: These findings indicate a strong association between episodes of binge eating and overweight/obesity, mainly among men.     

Adiposity, its related biologic risk factors, and suicide: a cohort study of 542,088 taiwanese adults

Recent studies in Western nations have shown inverse associations between body mass index (BMI, measured as weight (kg)/height (m)(2)) and suicide. However, it is uncertain whether the association is similar in non-Western settings, and the biologic pathways underlying the association are unclear. The authors investigated these issues in a cohort of 542,088 Taiwanese people 20 years of age or older who participated in a health check-up program (1994-2008); there were 573 suicides over a mean 8.1 years of follow up. There was a J-shaped association between BMI and suicide risk (P for the quadratic term = 0.033) but limited evidence of a linear association (adjusted hazard ratio per 1-standard-deviation increase = 0.95 (95% confidence interval: 0.85, 1.06)); compared with individuals whose BMI was 18.5-22.9, adjusted hazard ratios for those with a BMI <18.5 or ≥35 were 1.56 (95% confidence interval: 1.07, 2.28) and 3.62 (95% confidence interval: 1.59, 8.22), respectively. A high waist-to-hip ratio was associated with an increased risk of suicide. There was some evidence for a reverse J-shaped association of systolic blood pressure and high density lipoprotein cholesterol with suicide and an association of higher triglyceride level with increased suicide risk; these associations did not appear to mediate the associations of BMI and waist-to-hip ratio with suicide.     

Exercise, body mass index, caloric intake, and cardiovascular mortality

BACKGROUND: The association of physical inactivity and elevated body mass index (BMI) with cardiovascular disease (CVD) risk is well established. The relationship of dietary caloric intake and CVD risk is less certain. METHODS: The epidemiologic follow-up of the First National Health and Nutrition Examination Survey (1971-1992) was examined to determine the relationship of caloric intake, BMI, and physical activity to CVD mortality. Of 14,407 participants, 9790 subjects aged 25 to 74 years met inclusion criteria. The CVD mortality rate was the outcome. RESULTS: During the 17 years of follow-up, there were 3183 deaths, 1531 of which were due to CVD (9.11/1000 person-years). People with relatively less physical activity, lower caloric intake, and who were overweight (BMI 25 to 29.9 kg/m(2)) and obese (BMI > or =30 kg/m(2)) had a less favorable baseline CVD risk profile than did those who were more active and of normal weight and had greater caloric intake. Age- and race/ethnicity-adjusted CVD mortality rates were highest among those with the least physical activity and lowest caloric intake, and who were overweight or obese. Moreover, subjects of normal weight who exercised most were more likely to have high caloric intake and lower CVD mortality (5.9 vs 14.7 per 1000 person-years, p =0.01) than subjects who were obese and exercised least. In Cox regression analysis, controlling for relevant CVD risk factors, least physical activity was independently associated with increased CVD mortality (hazard ratio=1.32, 95% confidence interval [CI]=1.13-1.53); and obesity was associated with increased CVD mortality (hazard ratio=1.24, 95% CI=1.06-1.44). Although highest dietary caloric intake was associated with reduced CVD mortality (hazard ratio=0.83, 95% CI=0.74-0.93), after adjusting for physical activity and BMI, there was no significant association of highest caloric intake with CVD mortality (hazard ratio=0.91, 95% CI=0.81-1.01). CONCLUSIONS: In this large general population sample, lower levels of physical activity and obesity were independently associated with decreased CVD survival. Moreover, when BMI, physical activity, and other relevant characteristics were taken into account, caloric intake was not related to CVD mortality.     

Anthropometrics and prostate cancer risk

Studies on obesity and prostate cancer risk are inconsistent, perhaps because of differential effects on aggressive and nonaggressive cancers. Participants included 34,754 men residing in Washington State (aged 50-76 years at baseline) in a prospective cohort study who were recruited between 2000 and 2002; 383 developed aggressive (regional/distant stage or Gleason sum 7-10) and 437 developed nonaggressive disease through December 2004. Compared with normal-weight men (body mass index (kg/m(2)) <25), obese men (> or = 30 kg/m(2)) had a reduced risk of nonaggressive disease (hazard ratio = 0.69, 95% confidence interval: 0.52, 0.93; p for trend = 0.01). Overweight men (25-29.9 kg/m(2)) had an increased risk of aggressive disease (hazard ratio = 1.4, 95% confidence interval: 1.1, 1.8), but there was no increased risk for obese men (p for trend = 0.69). Body mass index of >25 at age 18 years was associated with increased risk of aggressive prostate cancer; obesity at ages 30 and 45, but not 18, years was associated with reduced risk of nonaggressive prostate cancer. Height (fourth vs. first quartile) was associated with an increased risk of total prostate cancer (hazard ratio = 1.3, 95% confidence interval: 1.1, 1.6), which did not differ by aggressiveness. There were no associations of prostate cancer with age at which maximum height was reached. Results from this study demonstrate the complexity of prostate cancer epidemiology and the importance of examining risk factors by tumor characteristics.     

Association of body mass index measured in childhood, adolescence, and young adulthood with risk of ischemic heart disease and stroke: findings from 3 historical cohort studies

BACKGROUND: It is unclear whether early life body mass index (BMI; in kg/m(2)) is associated with adult cardiovascular disease. OBJECTIVE: The objective was to assess the association of early life BMI with the risk of ischemic heart disease (IHD) and stroke. DESIGN: The association between early life BMI and risk of adult mortality from IHD and stroke was assessed in 3 historical cohort studies in which height and weight had been assessed by using standard procedures. Participants were traced and linked to national mortality data. Participants in the 3 cohorts were born between 1922 and 1937, 1927 and 1956, and 1928 and 1950 and were aged 2-15, 9-18, and 16-22 y, respectively, at the time of assessment of their height and weight. RESULTS: Participants in all 3 cohorts had mean BMIs similar to those reported for contemporary children and young adults, but fewer of the cohort participants were overweight or obese. BMI was not associated with future risk of IHD or stroke in any cohort. The pooled (all 3 cohorts) adjusted hazard ratio per SD of early life BMI was 1.09 (95% CI: 1.01, 1.19) for IHD and 0.94 (95% CI: 0.82, 1.08) for stroke. The pooled hazard ratio of IHD when participants who were overweight or obese for their age were compared with all other participants was 1.34 (95% CI: 0.95, 1.91), and no association was found between overweight or obesity and stroke risk. The effects of BMI did not vary by cohort or by age. CONCLUSION: These results do not provide strong evidence that being overweight or obese in childhood is associated with future cardiovascular disease risk.     

The association between neck pain intensity, physical functioning, depressive symptomatology and time-to-claim-closure after whiplash

Time-to-claim-closure is a common outcome in cohort studies of whiplash injuries. However, its relationship to health recovery is unknown. We investigated the association between neck pain, physical functioning, depressive symptomatology and time-to-claim-closure in a Saskatchewan cohort of 5398 whiplash claimants in 1994-1995. Participants were surveyed five times over 1 year. In 1995, the insurance system changed from tort to no-fault, eliminating compensation for pain and suffering. Under tort, a 10-point increase in pain reduced the claim-closure rate by 13-24% while a 10-point increase in physical functioning increased it by 17%. Depressive symptomatology reduced the claim-closure rate by 37%. Under no-fault, a 10-point increase in pain reduced the claim-closure rate by 18% while a 10-point increase in physical functioning increased it by 10-35%. The presence of depressive symptomatology reduced the claim-closure rate by 36%. The results suggests lower pain, better function and the absence of depressive symptoms are strongly associated with faster time-to-claim-closure and recovery after whiplash, independent of the insurance system.     

Body mass index in young adulthood and premature death: analyses of the US National Health Interview Survey linked mortality files

Knowledge of the association between body mass index (weight (kg)/height (m)(2)) and premature death in young adulthood is very limited, especially for specific causes of death. Using the US National Health Interview Survey linked mortality files, the authors examined the relation between body mass index and premature death from all causes, cardiovascular disease (CVD), and cancer among 112,328 persons aged 18-39 years who participated in the National Health Interview Survey in the years 1987, 1988, and 1990-1995. During an average of 16 years of follow-up (ending on December 31, 2006), there were 3,178 deaths: 573 from CVD and 733 from cancer. Hazard ratios and 95% confidence intervals were estimated using multivariate proportional hazards models adjusting for age, gender, race/ethnicity, education, and smoking status. In analyses restricted to participants who had never smoked, the hazard ratios for death from all causes were 1.07 (95% confidence interval (CI): 0.91, 1.26) for overweight participants, 1.41 (95% CI: 1.16, 1.73) for obese participants, and 2.46 (95% CI: 1.91, 3.16) for extremely obese participants, compared with those of normal weight. Monotonically increasing risks for excess body weight were also observed for deaths from cancer and CVD. The associations found in this young cohort were much stronger than those in middle-aged or older populations.     

Association between Dietary Intake of Flavonoids and Cancer Recurrence among Breast Cancer Survivors

Intake of flavonoids is associated with the incidence of breast cancer, but the association between the intake of flavonoids and cancer recurrence is unclear. This study aimed to investigate the hypothesis that intake of flavonoids and flavonoid-rich foods is negatively associated with cancer recurrence. Among 572 women who underwent breast cancer surgery, 66 patients had a cancer recurrence. Dietary data were collected using a structured 24-h dietary recall, and intake of flavonoids was calculated based on the Korea Rural Development Administration flavonoid database. Among overweight and obese patients, disease-free survival was associated with intake of flavonoids (p = 0.004) and flavonoid-rich foods (p = 0.003). Intake of flavonoids (hazard ratio (HR) = 0.249, 95% confidence interval (CI): 0.09–0.64) and flavonoid-rich foods (HR = 0.244, 95% CI: 0.09–0.66) was negatively associated with cancer recurrence after adjusting for confounding factors in overweight and obese patients. Consumption of flavonoids and flavonoid-rich foods was lower in overweight and obese patients with cancer recurrence than those without recurrence and in normal-weight patients. This study suggests that intake of flavonoids and flavonoid-rich foods could have beneficial effects on cancer recurrence in overweight and obese breast cancer survivors.     

Prenatal smoking and risk of intrapartum stillbirth

The purpose of this study was to examine the association between prenatal smoking and intrapartum stillbirth by the use of a cohort of singleton births in Missouri from 1978 through 1997. Overall, the authors identified a total of 7,325 counts of stillbirth, yielding a stillbirth rate of 4.4 per 1,000. The timing of the occurrence of the stillbirth to onset of labor was specified in 85.6% (n = 6,273). Of these, 1,070 (17.0%) occurred intrapartum. Smoking mothers were 50% more likely to experience intrapartum fetal death as compared with nonsmoking gravidas (adjusted hazard ratio = 1.5; 95% confidence interval = 1.3-1.7). Women who smoked 10 to 19 cigarettes per day were at the highest risk of experiencing intrapartum stillbirth (adjusted hazard ratio = 1.7 [95% confidence interval = 1.4-2.0]). Our findings underscore the need for increased smoking-cessation education efforts targeted toward pregnant women.     

Association between body mass index and acute traumatic workplace injury in hourly manufacturing employees

In this study, the authors examined the distribution and odds of occupational injury among hourly employees of a US aluminum manufacturing company by body mass index (weight (kg)/height (m)(2)). In 2002, height and weight data on 7,690 workers at eight plants were extracted from medical records from annual physicals, and body mass index was categorized. Information on traumatic injuries recorded between January 1, 2002, and December 31, 2004, was obtained from a company injury surveillance system. Twenty-nine percent of the employees (n = 2,221) sustained at least one injury. Approximately 85 percent of injured workers were classified as overweight or obese. The odds of injury in the highest obesity group as compared with the ideal body mass index group were 2.21 (95% confidence interval: 1.34, 3.53), after adjustment for sex, age, education, smoking, physical demands of the job, plant process and location, time since hire, time in the job, and significant interaction terms. Injuries to the leg or knee were especially prevalent among members of this very obese group. Research findings support an association between body mass index and traumatic workplace injuries among manufacturing employees. Workplace safety personnel might consider adding policies or programs that address weight reduction and maintenance as part of ongoing comprehensive workplace safety strategies.     

Sports, smoking, and overweight during adolescence as predictors of sciatica in adulthood: a 28-year follow-up study of a birth cohort

Lifestyle factors such as smoking, obesity, and level of physical activity predict low back pain (LBP) and sciatica. The authors investigated whether participating in sports, smoking, and being overweight or obese at 14 years of age predicted hospitalizations due to LBP or sciatica in adulthood. In 1980, at the age of 14 years, a total of 11,399 members of the 1966 Northern Finland Birth Cohort returned the postal questionnaire. Patients from the 1966 Northern Finland Birth Cohort who were hospitalized because of LBP or sciatica were followed to the end of 2008 through the Finnish Hospital Discharge Register. Data were analyzed using Cox's proportional hazards multistate model with the Markov clock forward time scale. During follow-up, 119 females (2.7%) and 254 males (5.6%) had been hospitalized at least once because of LBP or sciatica. Among females, overweight was associated with an increased risk of second-time hospitalization for surgical treatment for sciatica (hazard ratio = 7.1, 95% confidence interval: 1.5, 34.4). Among males, smoking was associated with an increased risk of first-time nonsurgical hospitalization (hazard ratio = 1.8, 95% confidence interval: 1.2, 2.7) and second-time surgical hospitalization (hazard ratio = 3.2, 95% confidence interval: 1.2, 8.2). The authors found potentially modifiable risk factors in adolescence that predicted hospital treatments for low back disorders during adolescence and young adulthood.     

Age at menopause, body mass index, and the risk of colorectal cancer mortality in the Dutch Diagnostisch Onderzoek Mammacarcinoom (DOM) cohort

We investigated whether age at menopause is associated with subsequent mortality from colorectal cancer along with the possible modification of this association by body mass index. Our data are from the Diagnostisch Onderzoek Mammacarcinoom cohort of 10,671 postmenopausal women in the Netherlands, enrolled between 1974 and 1977, with a median follow-up of 18 years. During this follow-up, 95 women died of colorectal cancer. Women 49 years of age or older at menopause showed a lower risk of colorectal cancer mortality compared with women younger than 49 at menopause. This protective effect, however, was found only among nonoverweight women (< or =24 kg/m2), for whom the hazard ratio was 0.46 (95% confidence interval = 0.21-1.03). In larger women, the hazard ratio was 1.17 (95% confidence interval = 0.68-2.00).     

Body mass index and use of mammography screening in the United States

BACKGROUND: Obese and underweight women may be less likely to seek cancer screening because of health status, self-perception, and body image related to non-desirable weight. This study examined the relationship between body mass index (BMI) and mammography screening, using the data from the year 2000 United States National Health Interview Survey. METHODS: This study included 7692 white and 1496 black female participants aged 40-80, who were randomly selected. Body mass index (kg/m2), based on self-reported weight and height, was compared between women with and without a mammogram in the past 2 years using logistic regression. RESULTS: Compared to women with normal body mass index, underweight and extremely obese women were more likely to have no screening mammograms in the past 2 years (odds ratio (OR) = 1.8, 95% confidence interval (CI), 1.2-2.6 for underweight women; odds ratio = 1.3, 95% confidence interval, 1.0-1.8 for extremely obese women). When data were analyzed by race, the odds ratio estimates were 1.8 for underweight white women (95% confidence interval, 1.3-2.7) and 1.4 for extremely obese white women (95% confidence interval, 1.0-1.9). The corresponding odds ratio estimates were close to 1.0 for black women. CONCLUSIONS: Underweight and extreme obesity may increase the risk of underusing screening mammography. The association between body mass index especially underweight and underuse of mammography might exist primarily in white women.     

White blood cell count and risk for all-cause, cardiovascular, and cancer mortality in a cohort of Koreans

The authors conducted a 10-year prospective cohort study of mortality in relation to white blood cell counts of 437,454 Koreans, aged 40-95 years, who received health insurance from the National Health Insurance Corporation and were medically evaluated in 1993 or 1995, with white blood cell measurement. The main outcome measures were mortality from all causes, all cancers, and all atherosclerotic cardiovascular diseases (ASCVD). Hazard ratios and 95% confidence intervals were calculated using Cox proportional hazards models with adjustment for age and potential confounders. During follow-up, 48,757 deaths occurred, with 15,507 deaths from cancer and 11,676 from ASCVD. For men and women, white blood cell count was associated with all-cause mortality and ASCVD mortality but not with cancer mortality. In healthy nonsmokers, a graded association between a higher white blood cell count and a higher risk of ASCVD was observed in men (highest vs. lowest quintile: hazard ratio = 2.10, 95% confidence interval: 1.50, 2.94) and in women (hazard ratio = 1.35, 95% confidence interval: 1.17, 1.56). In healthy smokers, a graded association between a higher white blood cell count and a higher risk of ASCVD was also observed in men (highest vs. lowest quintile: hazard ratio = 1.46, 95% confidence interval: 1.25, 1.72). These findings indicate that the white blood cell count is an independent risk factor for all-cause mortality and for ASCVD mortality.     

Predictors of follow-up and assessment of selection bias from dropouts using inverse probability weighting in a cohort of university graduates

Dropouts in cohort studies can introduce selection bias. In this paper, we aimed (i) to assess predictors of retention in a cohort study (the SUN Project) where participants are followed-up through biennial mailed questionnaires, and (ii) to evaluate whether differential follow-up introduced selection bias in rate ratio (RR) estimates. The SUN Study recruited 9907 participants from December 1999 to January 2002. Among them, 8647 (87%) participants answered the 2-year follow-up questionnaire. The presence of missing information in key variables at baseline, being younger, smoker, a marital status different of married, being obese/overweight and a history of motor vehicle injury were associated with being lost to follow-up, while a self-reported history of cardiovascular disease predicted a higher retention proportion. To assess whether differential follow-up affected RR estimates, we studied the association between body mass index and the risk of hypertension, using inverse probability weighting (IPW) to adjust for␣confounding and selection bias. Obese individuals had a higher crude rate of hypertension compared with␣normoweight participants (RR = 6.4, 95% confidence interval (CI): 3.9–10.5). Adjustment for confounding using IPW attenuated the risk of hypertension associated to obesity (RR = 2.4, 95% CI: 1.1–5.3). Additional adjustment for selection bias did not modify the estimations. In conclusion, we show that the follow-up through mailed questionnaires of a geographically disperse cohort in Spain is possible. Furthermore, we show that despite existing differences between retained or lost to follow-up participants this may not necessarily have an important impact on the RR estimates of hypertension associated to obesity.     

Smoking and the occurrence of Alzheimer's disease: cross-sectional and longitudinal data in a population-based study

The authors tested the hypothesis that smoking exerts a protective effect on Alzheimer's disease or dementia in a population-based cohort of 668 people aged 75-101 years (Sweden). Smoking was negatively associated with prevalent Alzheimer's disease (adjusted odds ratio = 0.6, 95% confidence interval 0.4-1.1) and dementia (adjusted odds ratio = 0.6, 95% confidence interval 0.4-1.0). Over 3-year follow-up (1989-1992), the hazard ratios of incident Alzheimer's disease and dementia due to smoking were 1.1 (95% confidence interval 0.5-2.4) and 1.4 (95% confidence interval 0.8-2.7). Mortality over 5-year follow-up was greater among smokers in demented (hazard ratio = 3.4) than nondemented (hazard ratio = 0.8) subjects. Smoking does not seem protective against Alzheimer's disease or dementia, and the cross-sectional association might be due to differential mortality.     

Can sustained weight loss in overweight individuals reduce the risk of diabetes mellitus?

Although rates of adult-onset diabetes mellitus increase with increasing obesity, there is little evidence that weight loss in overweight individuals can reduce their risk of developing diabetes. Using data from the Framingham Study, we examined the effects of sustained and nonsustained weight loss on risk of diabetes mellitus among 618 overweight (body mass index > or =27) subjects 30-50 years of age. To separate sustained from nonsustained weight loss, we examined weight change in two consecutive 8-year periods. Subjects who had stable weight (+/- 1 lb per year) during both periods served as the referent group for all analyses. Sustained weight loss led to a 37% lower risk of diabetes [relative risk (RR) = 0.63; 95% confidence interval = 0.34-1.2], and this effect was stronger for more obese (body mass index > or =29) subjects (RR = 0.38; 95% confidence interval = 0.18-0.81). Those who lost 8.1-15 lb had a 33% reduction in diabetes risk, whereas those losing more had a 51% reduction in risk. Regardless of the amount of weight lost, those who regained the lost weight had no reduction in diabetes risk (RR = 1.1 and 1.2 for those who lost 8.1-15 and >15 lb, respectively). We conclude that a modest amount of sustained weight loss can substantially reduce the risk of diabetes mellitus in overweight individuals.     

The Obesity Paradox in Colorectal Cancer Surgery: An Analysis of Korean Healthcare Big Data, 2012–2013

Although it is well known that obesity increases the risk of colorectal cancer, several studies have recently suggested that those who are overweight or class-one obese have better outcomes after surgery. However, the impact of obesity on the success of colorectal cancer surgery remains controversial. The medical records of patients diagnosed with colorectal cancer who were treated surgically from 2012 through 2013 were retrospectively analyzed. Data from a total of 36,740 patients were provided by the Healthcare Big Data Hub of the Korean Health Insurance Review & Assessment Service. Multivariate analyses suggested that hospital length of stay (LOS) was significantly associated with age, cancer stage, and body mass index. The odds ratios of spending more than 2 weeks in the hospital for the overweight or class-one obese groups compared to the normal weight group were 0.903 (95% confidence interval, 0.866–0.941) and 0.887 (95% confidence interval, 0.851–0.924), respectively, while that of the underweight group was 1.280 (95% confidence interval, 1.202–1.362). The “obesity paradox” applies to colorectal cancer, as indicated by decreased hospital LOS of overweight and obese patients. This result suggests that there is a protective effect of nutritional status in obese patients, which contributes to recovery from colorectal cancer surgery.