Development of an Algorithm to Classify Colonoscopy Indication from Coded Health Care Data.

INTRODUCTION: Electronic health data are potentially valuable resources for evaluating colonoscopy screening utilization and effectiveness. The ability to distinguish screening colonoscopies from exams performed for other purposes is critical for research that examines factors related to screening uptake and adherence, and the impact of screening on patient outcomes, but distinguishing between these indications in secondary health data proves challenging. The objective of this study is to develop a new and more accurate algorithm for identification of screening colonoscopies using electronic health data. METHODS: Data from a case-control study of colorectal cancer with adjudicated colonoscopy indication was used to develop logistic regression-based algorithms. The proposed algorithms predict the probability that a colonoscopy was indicated for screening, with variables selected for inclusion in the models using the Least Absolute Shrinkage and Selection Operator (LASSO). RESULTS: The algorithms had excellent classification accuracy in internal validation. The primary, restricted model had AUC= 0.94, sensitivity=0.91, and specificity=0.82. The secondary, extended model had AUC=0.96, sensitivity=0.88, and specificity=0.90. DISCUSSION: The LASSO approach enabled estimation of parsimonious algorithms that identified screening colonoscopies with high accuracy in our study population. External validation is needed to replicate these results and to explore the performance of these algorithms in other settings.

Follow-up and clinical significance of unsatisfactory liquid-based Papanicolaou tests.

BACKGROUND: To the authors' knowledge, few studies to date have examined adherence to recommended guidelines for follow-up and outcomes after an unsatisfactory Papanicolaou (Pap) test (UPT) with liquid-based technologies. METHODS: Within 4 US health plans, the median time to follow-up and the percentage of patients with follow-up testing by 120 days was calculated after a UPT. Multivariable analyses evaluated the association between clinical factors and follow-up testing. The authors compared the risk of a diagnosis of cervical intraepithelial neoplasia of type 2 or worse (CIN2+) after a UPT with the risk after a satisfactory Pap test while controlling for study site, test year, and other covariates. RESULTS: A total of 634,644 Pap tests performed between 2004 and 2010 were included in the current study. Of 1442 UPTs, 53.4% had follow-up testing within 120 days; follow-up differed across the health plans (P<.001) and was found to be higher among patients aged <50 years (57.2% vs 48.8%; P = .01) and those with positive human papillomavirus (HPV) results (84.6% vs 53.9; P <.01). The risk of CIN2+ was similar for patients with both unsatisfactory and satisfactory Pap tests. However, after a UPT, the variables of age <50 years, having no previous history of Pap testing, having a history of a previous abnormal Pap test, and positive HPV status were all found to be risk factors for CIN2+; a positive HPV test was found to be the strongest risk factor for developing CIN2+. A negative HPV test result was protective for a CIN2+ diagnosis. CONCLUSIONS: Various clinical factors associated with the risk of CIN2+ appear to influence the receipt of follow-up after a UPT. HPV test results in patients with UPTs might be used in follow-up strategies; specifically, a negative test result might reduce the urgency for repeat Pap testing.

Impact of hypertension on healthcare costs among children.

OBJECTIVES: Despite the significant prevalence of elevated blood pressure (BP) and body mass index (BMI) in children, few studies have assessed their combined impact on healthcare costs. This study estimates healthcare costs related to BP and BMI in children and adolescents. STUDY DESIGN: Prospective dynamic cohort study of 71,617 children aged 3 to 17 years with 208,800 child years of enrollment in integrated health systems in Colorado or Minnesota between January 1, 2007, and December 31, 2011. METHODS: Generalized linear models were used to calculate standardized annual estimates of total, inpatient, outpatient, and pharmacy costs, outpatient utilization, and receipt of diagnostic and evaluation tests associated with BP status and BMI status. Results: Total annual costs were significantly lower in children with normal BP ($736, SE = $15) and prehypertension ($945, SE = $10) than children with hypertension ($1972, SE = $74) (P <.001, each comparison), adjusting for BMI. Total annual cost for children below the 85th percentile of BMI ($822, SE = $8) was significantly lower than for children between the 85th and 95th percentiles ($954, SE = $45) and for children at or above the 95th percentile ($937, SE = $13) (P <.001, each), adjusting for HT. CONCLUSIONS: This study shows strong associations of prehypertension and hypertension, independent of BMI, with healthcare costs in children. Although BMI status was also statistically significantly associated with costs, the major influence on cost in this large cohort of children and adolescents was BP status. Costs related to elevated BMI may be systematically overestimated in studies that do not adjust for BP status.

Severe obesity in children: prevalence, persistence and relation to hypertension.

BACKGROUND: Newer approaches for classifying gradations of pediatric obesity by level of body mass index (BMI) percentage above the 95th percentile have recently been recommended in the management and tracking of obese children. Examining the prevalence and persistence of severe obesity using such methods along with the associations with other cardiovascular risk factors such as hypertension is important for characterizing the clinical significance of severe obesity classification methods. METHODS: This retrospective study was conducted in an integrated healthcare delivery system to characterize obesity and obesity severity in children and adolescents by level of body mass index (BMI) percentage above the 95th BMI percentile, to examine tracking of obesity status over 2-3 years, and to examine associations with blood pressure. Moderate obesity was defined by BMI 100-119% of the 95th percentile and severe obesity by BMI ≥120% × 95th percentile. Hypertension was defined by 3 consecutive blood pressures ≥95th percentile (for age, sex and height) on separate days and was examined in association with obesity severity. RESULTS: Among 117,618 children aged 6-17 years with measured blood pressure and BMI at a well-child visit during 2007-2010, the prevalence of obesity was 17.9% overall and was highest among Hispanics (28.9%) and blacks (20.5%) for boys, and blacks (23.3%) and Hispanics (21.5%) for girls. Severe obesity prevalence was 5.6% overall and was highest in 12-17 year old Hispanic boys (10.6%) and black girls (9.5%). Subsequent BMI obtained 2-3 years later also demonstrated strong tracking of severe obesity. Stratification of BMI by percentage above the 95th BMI percentile was associated with a graded increase in the risk of hypertension, with severe obesity contributing to a 2.7-fold greater odds of hypertension compared to moderate obesity. CONCLUSION: Severe obesity was found in 5.6% of this community-based pediatric population, varied by gender and race/ethnicity (highest among Hispanics and blacks) and showed strong evidence for persistence over several years. Increasing gradation of obesity was associated with higher risk for hypertension, with a nearly three-fold increased risk when comparing severe to moderate obesity, underscoring the heightened health risk associated with severe obesity in children and adolescents.

Approaches for classifying the indications for colonoscopy using detailed clinical data.

BACKGROUND: Accurate indication classification is critical for obtaining unbiased estimates of colonoscopy effectiveness and quality improvement efforts, but there is a dearth of published systematic classification approaches. The objective of this study was to evaluate the effects of data-source and adjudication on indication classification and on estimates of the effectiveness of screening colonoscopy on late-stage colorectal cancer diagnosis risk. METHODS: This was an observational study in members of four U.S. health plans. Eligible persons (n = 1039) were age 55-85 and had been enrolled for 5 years or longer in their health plans during 2006-2008. Patients were selected based on late-stage colorectal cancer diagnosis in a case-control design; each case patient was matched to 1-2 controls by study site, age, sex, and health plan enrollment duration. Reasons for colonoscopies received in the 10-year period before the reference date were collected from three medical records sources (progress notes; referral notes; procedure reports) and categorized using an algorithm, with committee adjudication of some tests. We evaluated indication classification concordance before and after adjudication and used logistic regressions with the Wald Chi-square test to compare estimates of the effects of screening colonoscopy on late-stage colorectal cancer diagnosis risk for each of our data sources to the adjudicated indication. RESULTS: Classification agreement between each data-source and adjudication was 78.8-94.0% (weighted kappa = 0.53-0.72); the highest agreement (weighted kappa = 0.86-0.88) was when information from all data sources was considered together. The choice of data-source influenced the association between screening colonoscopy and late-stage colorectal cancer diagnosis; estimates based on progress notes were closest to those based on the adjudicated indication (% difference in regression coefficients = 2.4%, p-value = 0.98), as compared to estimates from only referral notes (% difference in coefficients = 34.9%, p-value = 0.12) or procedure reports (% difference in coefficients = 27.4%, p-value = 0.23). CONCLUSION: There was no single gold-standard source of information in medical records. The estimates of colonoscopy effectiveness from progress notes alone were the closest to estimates using adjudicated indications. Thus, the details in the medical records are necessary for accurate indication classification.

Body mass and weight change in adults in relation to mortality risk.

Using data from the National Institutes of Health-AARP Diet and Health Study, we evaluated the influence of adulthood weight history on mortality risk. The National Institutes of Health-AARP Diet and Health Study is an observational cohort study of US men and women who were aged 50-71 years at entry in 1995-1996. This analysis focused on 109,947 subjects who had never smoked and were younger than age 70 years. We estimated hazard ratios of total and cause-specific mortality for recalled body mass index (BMI; weight (kg)/height (m)(2)) at ages 18, 35, and 50 years; weight change across 3 adult age intervals; and the effect of first attaining an elevated BMI at 4 successive ages. During 12.5 years' follow-up through 2009, 12,017 deaths occurred. BMI at all ages was positively related to mortality. Weight gain was positively related to mortality, with stronger associations for gain between ages 18 and 35 years and ages 35 and 50 years than between ages 50 and 69 years. Mortality risks were higher in persons who attained or exceeded a BMI of 25.0 at a younger age than in persons who reached that threshold later in adulthood, and risks were lowest in persons who maintained a BMI below 25.0. Heavier initial BMI and weight gain in early to middle adulthood strongly predicted mortality risk in persons aged 50-69 years.

Geographic variation in cardiovascular procedure use among Medicare fee-for-service vs Medicare Advantage beneficiaries.

IMPORTANCE: Little is known about how different financial incentives between Medicare Advantage and Medicare fee-for-service (FFS) reimbursement structures influence use of cardiovascular procedures. OBJECTIVE: To compare regional cardiovascular procedure rates between Medicare Advantage and Medicare FFS beneficiaries. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional study of Medicare beneficiaries older than 65 years between 2003-2007 comparing rates of coronary angiography, percutaneous coronary intervention (PCI), and coronary artery bypass graft (CABG) surgery across 32 hospital referral regions in 12 states. MAIN OUTCOMES AND MEASURES: Rates of coronary angiography, PCI, and CABG surgery. RESULTS: We evaluated a total of 878,339 Medicare Advantage patients and 5,013,650 Medicare FFS patients. Compared with Medicare FFS patients, Medicare Advantage patients had lower age-, sex-, race-, and income-adjusted procedure rates per 1000 person-years for angiography (16.5 [95% CI, 14.8-18.2] vs 25.9 [95% CI, 24.0-27.9]; P < .001) and PCI (6.8 [95% CI, 6.0-7.6] vs 9.8 [95% CI, 9.0-10.6]; P < .001) but similar rates for CABG surgery (3.1 [95% CI, 2.8-3.5] vs 3.4 [95% CI, 3.1-3.7]; P = .33). There were no significant differences between Medicare Advantage and Medicare FFS patients in the rates per 1000 person-years of urgent angiography (3.9 [95% CI, 3.6-4.2] vs 4.3 [95% CI, 4.0-4.6]; P = .24) or PCI (2.4 [95% CI, 2.2-2.7] vs 2.7 [95% CI, 2.5-2.9]; P = .16). Procedure rates varied widely across hospital referral regions among Medicare Advantage and Medicare FFS patients. For angiography, the rates per 1000 person-years ranged from 9.8 to 40.6 for Medicare Advantage beneficiaries and from 15.7 to 44.3 for Medicare FFS beneficiaries. For PCI, the rates ranged from 3.5 to 16.8 for Medicare Advantage and from 4.7 to 16.1 for Medicare FFS. The rates for CABG surgery ranged from 1.5 to 6.1 for Medicare Advantage and from 2.5 to 6.0 for Medicare FFS. Across regions, we found no statistically significant correlation between Medicare Advantage and Medicare FFS beneficiary utilization for angiography (Spearman r = 0.19, P = .29) and modest correlations for PCI (Spearman r = 0.33, P = .06) and CABG surgery (Spearman r = 0.35, P = .05). Among Medicare Advantage beneficiaries, adjustment for additional cardiac risk factors had little influence on procedure rates. CONCLUSIONS AND RELEVANCE: Although Medicare beneficiaries enrolled in capitated Medicare Advantage programs had lower angiography and PCI procedure rates than those enrolled in Medicare FFS, the degree of geographic variation in procedure rates was substantial among Medicare Advantage beneficiaries and was similar in magnitude to that observed among Medicare FFS beneficiaries.

Effects of transitioning from conventional methods to liquid-based methods on unsatisfactory Papanicolaou tests: results from a multicenter US study.

BACKGROUND: Papanicolaou (Pap) testing has transitioned from conventional preparations (CPs) to liquid-based preparations (LBPs) because of the perceived superiority of LBPs. Many studies conclude that LBPs reduce unsatisfactory Pap tests; however, some believe that the evidence substantiating this claim is weak. The authors studied the effect of the transition from CPs to LBPs on the proportion of unsatisfactory Pap tests in 4 health care systems in the United States participating in the National Institutes of Health-funded Screening Effectiveness and Research in Community-Based Healthcare (SEARCH) project. METHODS: The study cohort consisted of 548,174 women ages 21 to 65 years who had 1443,725 total Pap tests between 2000 and 2010. Segmented regression analysis was used to estimate the effect of adopting LBPs on the proportion of unsatisfactory Pap tests after adjusting for age. RESULTS: Three sites that implemented SurePath LBP experienced significant reductions in unsatisfactory Pap tests (estimated effect: site 1, -2.46%; 95% confidence interval [CI], -1.47%, -3.45%; site 2, -1.78%; 95% CI, -1.54%, -2.02%; site 3, -8.25%; 95% CI, -7.33%, -9.17%). The fourth site that implemented ThinPrep LBP did not experience a reduction in unsatisfactory Pap tests. The relative risk of an unsatisfactory Pap test in women aged ≥ 50 years increased after the transition to LBPs (SurePath: relative risk, 2.1; 95% CI, 1.9-2.2; ThinPrep: relative risk, 1.7; 95% CI, 1.5-2.0). CONCLUSIONS: The observed changes in the proportion of unsatisfactory Pap tests varied across the participating sites and depended on the type of LBP technology, the age of women, and the rates before the implementation of this technology.

Body mass index at different adult ages, weight change, and colorectal cancer risk in the National Institutes of Health-AARP Cohort.

The authors investigated the relations of body mass index at different ages and adult weight change to incident colorectal cancer risk in the prospective National Institutes of Health-AARP Diet and Health Study (1995-1996), using a subcohort with repeated recall weights (273,679 participants; mean baseline age = 62.8 years). During 2,509,662 person-years follow-up, 4076 incident colorectal cancers were ascertained. For men, an increased risk of colon cancer but not rectal cancer was associated with body mass index at baseline age (per 5-kg/m(2) increase, hazard ratio (HR) = 1.18, 95% confidence interval (CI): 1.11, 1.25), at age 50 years (HR = 1.18, 95% CI: 1.10, 1.26), and at age 35 years (HR = 1.16, 95% CI: 1.07, 1.25) but less so at age 18 years. Weight gained between the ages of 18 and 35 years and between 18 years of age and the baseline age was associated with an increased risk of colon cancer in men (per 0.5-kg/year increase, HR = 1.18, 95% CI: 1.11, 1.25 and HR = 1.29, 95% CI: 1.16, 1.56, respectively). For women, relations throughout were weaker than those observed for men. These findings suggest that weight gains during early to middle adulthood have important influences on colon cancer risk, especially in men.

Cancer incidence and mortality after gastric bypass surgery.

Despite weight loss recommendations to prevent cancer, cancer outcome studies after intentional weight loss are limited. Recently, reduced cancer mortality following bariatric surgery has been reported. This study tested whether reduced cancer mortality following gastric bypass was due to decreased incidence. Cancer incidence and mortality data through 2007 from the Utah Cancer Registry (UCR) were compared between 6,596 Utah patients who had gastric bypass (1984-2002) and 9,442 severely obese persons who had applied for Utah Driver's Licenses (1984-2002). Study outcomes included incidence, case-fatality, and mortality for cancer by site and stage at diagnosis of all gastric bypass patients, compared to nonoperated severely obese controls. Follow-up was over a 24-year period (mean 12.5 years). Total cancer incidence was significantly lower in the surgical group compared to controls (hazard ratio (HR) = 0.76; confidence interval (CI) 95%, 0.65-0.89; P = 0.0006). Lower incidence in surgery patients vs. controls was primarily due to decreased incidence of cancer diagnosed at regional or distant stages. Cancer mortality was 46% lower in the surgery group compared to controls (HR = 0.54; CI 95%, 0.37-0.78; P = 0.001). Although the apparent protective effect of surgery on risk of developing cancer was limited to cancers likely known to be obesity related, the inverse association for mortality was seen for all cancers. Significant reduction in total cancer mortality in gastric bypass patients compared with severely obese controls was associated with decreased incidence, primarily among subjects with advanced cancers. These findings suggest gastric bypass results in lower cancer risk, presumably related to weight loss, supporting recommendations for reducing weight to lower cancer risk.

The combined relations of adiposity and smoking on mortality.

BACKGROUND: Smoking and high adiposity are strong independent health risk factors but are also interrelated. Smoking is related to a lower body mass index (BMI) but not necessarily with a smaller waist circumference. Smoking cessation is associated with increased body weight and a substantial increase in waist circumference. How this affects mortality risk is unknown. OBJECTIVE: This study examined the combined relations of smoking status with BMI and waist circumference and smoking status to all-cause mortality. DESIGN: Data were from 149 502 men and 88 184 women aged 51-72 y participating in the National Institutes of Health-AARP Diet and Health Study. All-cause mortality was assessed over 10 y of follow-up from 1996 to 2006. RESULTS: Current smokers with a BMI (in kg/m(2)) <18.5 or >or=35 had a mortality risk 6-8 times that of persons within the normal BMI range who never smoked. Current smokers with a large waist circumference had a mortality risk about 5 times that of never smokers with a waist circumference in the second quintile. CONCLUSION: Both smoking and adiposity are independent predictors of mortality, but the combination of current or recent smoking with a BMI >or= 35 or a large waist circumference is related to an especially high mortality risk.

Body size and renal cell cancer incidence in a large US cohort study.

Renal cell cancer (RCC) incidence has increased in the United States over the past three decades. The authors analyzed the association between body mass index (BMI) and invasive RCC in the National Institutes of Health (NIH)-AARP Diet and Health Study, a large, prospective cohort aged 50-71 years at baseline initiated in 1995-1996, with follow-up through December 2003. Detailed analyses were conducted in a subcohort responding to a second questionnaire, including BMI at younger ages (18, 35, and 50 years); weight change across three consecutive age intervals; waist, hip, and waist-to-hip ratio; and height at age 18 years. Incident RCC was diagnosed in 1,022 men and 344 women. RCC was positively and strongly related to BMI at study baseline. Among subjects analyzed in the subcohort, RCC associations were strongest for baseline BMI and BMI recalled at age 50 years and were successively attenuated for BMI recalled at ages 35 and 18 years. Weight gain in early (18-35 years of age) and mid- (35-50 years of age) adulthood was strongly associated with RCC, whereas weight gain after midlife (age 50 years to baseline) was unrelated. Waist-to hip ratio was positively associated with RCC in women and with height at age 18 years in both men and women.

Physical activity during adulthood and adolescence in relation to renal cell cancer.

Evidence for a relation between physical activity and renal cell cancer has been inconsistent. The authors examined physical activity in relation to renal cell cancer in a large, prospective US cohort study of 482,386 participants (289,503 men and 192,883 women) aged 50-71 years at baseline (1995-1996). At baseline, participants reported their frequency of exercise of at least 20 minutes' duration, intensity of daily routine activity, and frequency of physical activity during adolescence. During 8.2 years of follow-up (through December 2003), 1,238 cases of renal cell cancer were ascertained. In multivariate Cox regression models adjusted for renal cell cancer risk factors, the authors observed that current exercise, routine physical activity, and activity during adolescence were associated with a reduced risk of renal cell cancer. The multivariate relative risks for the highest activity level as compared with the lowest were 0.77 (95% confidence interval (CI): 0.64, 0.92; p(trend) = 0.10) for current exercise, 0.84 (95% CI: 0.57, 1.22; p(trend) = 0.03) for routine physical activity, and 0.82 (95% CI: 0.68, 1.00; p(trend) = 0.05) for activity during adolescence. The authors conclude that increased physical activity, including activity during adolescence, is associated with reduced risk of renal cell cancer.

Waist circumference and mortality.

The authors examined the association between waist circumference and mortality among 154,776 men and 90,757 women aged 51-72 years at baseline (1996-1997) in the NIH-AARP Diet and Health Study. Additionally, the combined effects of waist circumference and body mass index (BMI; weight (kg)/height (m)(2)) were examined. All-cause mortality was assessed over 9 years of follow-up (1996-2005). After adjustment for BMI and other covariates, a large waist circumference (fifth quintile vs. second) was associated with an approximately 25% increased mortality risk (men: hazard ratio (HR) = 1.22, 95% confidence interval (CI): 1.15, 1.29; women: HR = 1.28, 95% CI: 1.16, 1.41). The waist circumference-mortality association was found in persons with and without prevalent disease, in smokers and nonsmokers, and across different racial/ethnic groups (non-Hispanic Whites, non-Hispanic Blacks, Hispanics, and Asians). Compared with subjects with a combination of normal BMI (18.5-<25) and normal waist circumference, those in the normal-BMI group with a large waist circumference (men: > or =102 cm; women: > or =88 cm) had an approximately 20% higher mortality risk (men: HR = 1.23, 95% CI: 1.08, 1.39; women: HR = 1.22, 95% CI: 1.09, 1.36). The finding that persons with a normal BMI but a large waist circumference had a higher mortality risk in this study suggests that increased waist circumference should be considered a risk factor for mortality, in addition to BMI.

Adiposity, adult weight change, and postmenopausal breast cancer risk.

BACKGROUND: Obesity is a risk factor for postmenopausal breast cancer, but the role of the timing and amount of adult weight change in breast cancer risk is unclear. METHODS: We prospectively examined the relations of adiposity and adult weight change to breast cancer risk among 99 039 postmenopausal women in the National Institutes of Health-AARP Diet and Health Study. Anthropometry was assessed by self-report in 1996. Through 2000, 2111 incident breast cancer cases were ascertained. RESULTS: Current body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared), BMI at ages 50 and 35 years, and waist-hip ratio were associated with increased breast cancer risk, particularly in women not using menopausal hormone therapy (MHT). Weight gained between age 18 years and the current age, between ages 18 and 35 years, between ages 35 and 50 years, and between age 50 years and the current age was consistently associated with increased breast cancer risk in MHT nonusers (relative risk [RR], 2.15; 95% confidence interval [CI], 1.35-3.42 for a >/=50-kg weight gain between age 18 years and the current age vs stable weight) but not in current MHT users. Risk associated with adult weight change was stronger in women with later vs earlier age at menarche (RR, 4.20; 95% CI, 2.05-8.64 for >/=15 years vs RR, 1.51; 95% CI, 1.11-2.06 for 11-12 years; P = .007 for interaction). In MHT nonusers, the associations with current BMI and adult weight change were stronger for advanced disease than for nonadvanced disease (P = .009 [current BMI] and .21 [weight gain] for heterogeneity) and were stronger for hormone receptor-positive than hormone receptor-negative tumors (P < .001 for heterogeneity). CONCLUSION: Weight gain throughout adulthood is associated with increased postmenopausal breast cancer risk in MHT nonusers.

Body mass and colorectal cancer risk in the NIH-AARP cohort.

In most studies, body mass index (BMI) has been associated with increased risk of colorectal or colon cancer in men, but the relation is weaker and less consistent for women, possibly because of interactions with age or hormone replacement therapy. The authors examined the relation between BMI and colorectal cancer incidence in a large, prospective US cohort of 307,708 men and 209,436 women from the NIH-AARP Diet and Health Study. During follow-up of the cohort from 1995 to 2000, 2,314 cases of colorectal cancer were observed in men and 1,029 in women. BMI was related to increased risk of incident colon cancer, but not rectal cancer, for both men and women. For men, relative risks of colon cancer for a BMI of 18.5-<23, 23-<25, 25-<27.5, 27.5-<30, 30-<32.5, 32.5-<35, 35-<40, and > or = 40 kg/m(2) were 1.0 (referent), 1.11, 1.22, 1.44, 1.53, 1.57, 1.71, and 2.39, respectively (95% confidence interval: 1.59, 3.58; p-trend < 0.0005). Corresponding relative risks for women were 1.0, 1.20, 1.29, 1.31, 1.28, 1.13, 1.46, and 1.49 (95% confidence interval: 0.98, 2.25; p-trend = 0.02). BMI was related to colon cancer risk for younger (aged 50-66 years) but not older (aged 67-71 years) women. The association was not modified by hormone replacement therapy in women or physical activity in men or women.

Overweight, obesity, and mortality in a large prospective cohort of persons 50 to 71 years old.

BACKGROUND: Obesity, defined by a body-mass index (BMI) (the weight in kilograms divided by the square of the height in meters) of 30.0 or more, is associated with an increased risk of death, but the relation between overweight (a BMI of 25.0 to 29.9) and the risk of death has been questioned. METHODS: We prospectively examined BMI in relation to the risk of death from any cause in 527,265 U.S. men and women in the National Institutes of Health-AARP cohort who were 50 to 71 years old at enrollment in 1995-1996. BMI was calculated from self-reported weight and height. Relative risks and 95 percent confidence intervals were adjusted for age, race or ethnic group, level of education, smoking status, physical activity, and alcohol intake. We also conducted alternative analyses to address potential biases related to preexisting chronic disease and smoking status. RESULTS: During a maximum follow-up of 10 years through 2005, 61,317 participants (42,173 men and 19,144 women) died. Initial analyses showed an increased risk of death for the highest and lowest categories of BMI among both men and women, in all racial or ethnic groups, and at all ages. When the analysis was restricted to healthy people who had never smoked, the risk of death was associated with both overweight and obesity among men and women. In analyses of BMI during midlife (age of 50 years) among those who had never smoked, the associations became stronger, with the risk of death increasing by 20 to 40 percent among overweight persons and by two to at least three times among obese persons; the risk of death among underweight persons was attenuated. CONCLUSIONS: Excess body weight during midlife, including overweight, is associated with an increased risk of death.