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The role of lifestyle risk factors in prostate cancer risk remains elusive despite a large number of epidemiologic studies. In a pooled analysis of data from South and East Asian countries published in this issue, Fowke et al. (Am J Epidemiol. 2015;182(5):381-389) found no evidence for an association between prostate cancer mortality and obesity, alcohol, or smoking. Prostate cancer screening is very uncommon in these countries, and previous evidence for associations with lifestyle factors comes primarily from studies carried out in North America, where screening is very common. Fowke et al. concluded that screening biases are likely to explain the differences in study results. In this commentary, we discuss the potential influence of population-based cancer screening programs in estimates of association from epidemiologic studies. This highlights the importance of carefully considering the impact of screening in the analysis and interpretation of results, in order to advance our understanding of the etiology of cancers that can be detected by screening. [ABSTRACT FROM AUTHOR]

Background: A high body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) is associated with increased mortality from cardiovascular disease and certain cancers, but the precise relationship between BMI and all-cause mortality remains uncertain. Methods: We used Cox regression to estimate hazard ratios and 95% confidence intervals for an association between BMI and all-cause mortality, adjusting for age, study, physical activity, alcohol consumption, education, and marital status in pooled data from 19 prospective studies encompassing 1.46 million white adults, 19 to 84 years of age (median, 58). Results: The median baseline BMI was 26.2. During a median follow-up period of 10 years (range, 5 to 28), 160,087 deaths were identified. Among healthy participants who never smoked, there was a J-shaped relationship between BMI and all-cause mortality. With a BMI of 22.5 to 24.9 as the reference category, hazard ratios among women were 1.47 (95 percent confidence interval [CI], 1.33 to 1.62) for a BMI of 15.0 to 18.4; 1.14 (95% CI, 1.07 to 1.22) for a BMI of 18.5 to 19.9; 1.00 (95% CI, 0.96 to 1.04) for a BMI of 20.0 to 22.4; 1.13 (95% CI, 1.09 to 1.17) for a BMI of 25.0 to 29.9; 1.44 (95% CI, 1.38 to 1.50) for a BMI of 30.0 to 34.9; 1.88 (95% CI, 1.77 to 2.00) for a BMI of 35.0 to 39.9; and 2.51 (95% CI, 2.30 to 2.73) for a BMI of 40.0 to 49.9. In general, the hazard ratios for the men were similar. Hazard ratios for a BMI below 20.0 were attenuated with longer-term follow-up. Conclusions: In white adults, overweight and obesity (and possibly underweight) are associated with increased all-cause mortality. All-cause mortality is generally lowest with a BMI of 20.0 to 24.9. N Engl J Med 2010;363:2211-9. [ABSTRACT FROM AUTHOR]

A response by A. Berrington de Gonzalez and colleagues to letters to the editor about their article "Body-Mass Index and Mortality Among 1.46 Million White Adults" in the December 2, 2010 issue is presented.

Background: Reduction of premature mortality is a UN Sustainable Development Goal. Unlike other high-income countries, age-adjusted mortality in the USA plateaued in 2010 and increased slightly in 2015, possibly because of rising premature mortality. We aimed to analyse trends in mortality in the USA between 1999 and 2014 in people aged 25-64 years by age group, sex, and race and ethnicity, and to identify specific causes of death underlying the temporal trends.Methods: For this analysis, we used cause-of-death and demographic data from death certificates from the US National Center for Health Statistics, and population estimates from the US Census Bureau. We estimated annual percentage changes in mortality using age-period-cohort models. Age-standardised excess deaths were estimated for 2000 to 2014 as observed deaths minus expected deaths (estimated from 1999 mortality rates).Findings: Between 1999 and 2014, premature mortality increased in white individuals and in American Indians and Alaska Natives. Increases were highest in women and those aged 25-30 years. Among 30-year-olds, annual mortality increases were 2·3% (95% CI 2·1-2·4) for white women, 0·6% (0·5-0·7) for white men, and 4·3% (3·5-5·0) and 1·9% (1·3-2·5), respectively, for American Indian and Alaska Native women and men. These increases were mainly attributable to accidental deaths (primarily drug poisonings), chronic liver disease and cirrhosis, and suicide. Among individuals aged 25-49 years, an estimated 111 000 excess premature deaths occurred in white individuals and 6600 in American Indians and Alaska Natives during 2000-14. By contrast, premature mortality decreased substantially across all age groups in Hispanic individuals (up to 3·2% per year), black individuals (up to 3·9% per year), and Asians and Pacific Islanders (up to 2·6% per year), mainly because of declines in HIV, cancer, and heart disease deaths, resulting in an estimated 112 000 fewer deaths in Hispanic individuals, 311 000 fewer deaths in black individuals, and 34 000 fewer deaths in Asians and Pacific Islanders aged 25-64 years. During 2011-14, American Indians and Alaska Natives had the highest premature mortality, followed by black individuals.Interpretation: Important public health successes, including HIV treatment and smoking cessation, have contributed to declining premature mortality in Hispanic individuals, black individuals, and Asians and Pacific Islanders. However, this progress has largely been negated in young and middle-aged (25-49 years) white individuals, and American Indians and Alaska Natives, primarily because of potentially avoidable causes such as drug poisonings, suicide, and chronic liver disease and cirrhosis. The magnitude of annual mortality increases in the USA is extremely unusual in high-income countries, and a rapid public health response is needed to avert further premature deaths.Funding: US National Cancer Institute Intramural Research Program. [ABSTRACT FROM AUTHOR]