Kenneth F. Adams

Chinese translation The effectiveness of screening colonoscopy in average-risk adults is uncertain, particularly for right colon cancer. To examine the association between screening colonoscopy and risk for incident late-stage colorectal cancer (CRC). Nested case–control study. Four U.S. health plans. 1039 average-risk adults enrolled for at least 5 years in one of the health plans. Case patients were aged 55 to 85 years on their diagnosis date (reference date) of stage IIB or higher (late-stage) CRC during 2006 to 2008. One or 2 control patients were selected for each case patient, matched on birth year, sex, health plan, and prior enrollment duration. Receipt of CRC screening 3 months to 10 years before the reference date, ascertained through medical record audits. Case patients and control patients were compared on receipt of screening colonoscopy or sigmoidoscopy by using conditional logistic regression that accounted for health history, socioeconomic status, and other screening exposures. In analyses restricted to 471 eligible case patients and their 509 matched control patients, 13 case patients (2.8%) and 46 control patients (9.0%) had undergone screening colonoscopy, which corresponded to an adjusted odds ratio (AOR) of 0.29 (95% CI, 0.15 to 0.58) for any late-stage CRC, 0.36 (CI, 0.16 to 0.80) for right colon cancer, and 0.26 (CI, 0.06 to 1.11; P = 0.069) for left colon/rectum cancer. Ninety-two case patients (19.5%) and 173 control patients (34.0%) had screening sigmoidoscopy, corresponding to an AOR of 0.50 (CI, 0.36 to 0.70) overall, 0.79 (CI, 0.51 to 1.23) for right colon late-stage cancer, and 0.26 (CI, 0.14 to 0.48) for left colon cancer. The small number of screening colonoscopies affected the precision of the estimates. Screening with colonoscopy in average-risk persons was associated with reduced risk for diagnosis of incident late-stage CRC, including right-sided colon cancer. For sigmoidoscopy, this association was seen for left CRC, but the association for right colon late-stage cancer was not statistically significant. National Cancer Institute of the National Institutes of Health.

The association between body mass index (BMI) and mortality continues to defy easy characterization. In this issue, Sauvaget and colleagues 1 report elevated BMI to be unrelated to mortality risk in a rural Indian population. In fact, their results could be interpreted to suggest that overweight Asian-Indians have reduced mortality. At the same time, underweight (BMI <18.5 kg/m 2) was associated with increased risk. Given the attention paid to excess weight as a public health problem worldwide, the lack of association between elevated BMI and mortality may seem surprising. Studies in both Asia and the West have been mixed regarding the relation between mildly excessive BMI and mortality 2-4. Little data exist regarding the body mass-mortality relationship in India, although BMI was reported to be unrelated to mortality in an urban cohort, 5 similar to the findings in this issue. India is undergoing an epidemiologic transition in which chronic conditions replace communicable disease as major causes of morbidity and death. 6 In Kerala, the state in which this study took place, life expectancy approaches that of many Western industrialized nations (for example, in 2000, life expectancy at birth is 74.6 years in Kerala, 7 compared with 77 years in the US). 8 Indeed, data on the patterns of deaths in Kerala increasingly mirror those in the US. 9 Is the emerging concern regarding overweight and obesity in India overstated? To the contrary, evidence indicates that adiposity is increasing in India, that it is associated with cardio-metabolic risk factors, diabetes and cardiovascular disease, 10,11 and that mortality from these conditions is increasing. 12 Diabetes is a particular concern, both as a risk factor for cardiovascular disease and for the high human and economic cost of microvascular disease complications. While this study is

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.