Body mass index at early adulthood, subsequent weight change and cancer incidence and mortality

Abstract

Obesity later in adulthood is associated with increased risks of many cancers. However, the effect of body fatness in early adulthood, and change in weight from early to later adulthood on cancer risk later in life is less clear. We used data from 13,901 people aged 45-64 in the Atherosclerosis Risk in Communities cohort who at baseline (1987-1989) self-reported their weight at the age of 25 and had weight and height measured. Incident cancers were identified through 2006 and cancer deaths were ascertained through 2009. Multivariable Cox proportional hazard models were used to relate body mass index (BMI) at age 25 and percent weight change from age 25 to baseline to cancer incidence and mortality. After adjusting for weight change from age 25 until baseline, a 5 kg/m2 increment in BMI at age 25 was associated with a greater risk of incidence of all cancers in women [hazard ratio (95% confidence interval): 1.10 (1.02-1.20)], but not in men. Associations with incident endometrial cancer were strong [1.83 (1.47-2.26)]. After adjusting for BMI at age 25, a 5% increment in weight from age 25 to baseline was associated with a greater risk of incident post-menopausal breast cancer [1.05 (1.02-1.07)] and endometrial cancer [1.09 (1.04-1.14)] in women and incident colorectal cancer [1.05 (1.00-1.10)] in men. Excess weight during young adulthood and weight gain from young to older adulthood may be independently associated with subsequent cancer risk. Excess weight and weight gain in early adulthood should be avoided.

Adulthood Weight Change and Risk of Colorectal Cancer in the Nurses' Health Study and Health Professionals Follow-up Study

“…For weight gain since early adulthood, consistent with previous studies,(4, 6–8, 10, 11, 15) we found a positive association with CRC risk and the association was stronger in men than in women. Although it is possible that the older ages of men compared to women at cohort enrollment contribute to the larger elevation of CRC risk associated with weight gain, we did not find strong evidence that the association between weight change and CRC risk varied by age at baseline in either men or women (Supplementary Table 2).…”

“…Similarly, the influence of non-surgical weight loss on CRC remains inconclusive in prospective cohort studies, in which weight loss was typically considered only in a single category due to the small number of cases. (4, 6–10, 15, 33) To our knowledge, our findings provide the first population-based evidence that weight loss during adulthood may be associated with lower risk of CRC.…”

“…(2) Although similar patterns were seen for weight gain in some studies,(4, 10, 12–15) findings from others were inconsistent. (9, 13) In addition, in most studies body weight data were collected at only two time points to calculate weight change,(6–10, 14, 15) and therefore a more precise assessment of the timing of weight gain on CRC risk could not be determined.…”

Prospective cohort study of general and central obesity, weight change trajectory and risk of major cancers among Chinese women

“…(36) We found that an increased weight change trajectory during adulthood was associated with elevated risk of all cancers combined, breast cancer, particularly postmenopausal breast cancer, endometrial cancer, and possibly liver cancer and lymphatic and hematopoietic malignancy, independent of BMI at age 20 and other established risk factors. These results suggest that regardless of BMI at early adulthood, being obese in later life or gaining weight along the way increases the risk of several cancers, emphasizing the importance of maintaining a healthy weight during adulthood.…”

Risk Factors for Colorectal Cancer

“…Johnson et al [7] performed a meta-analysis including 23 studies evaluating BMI and CRC risk finding that for every 8 kg/m2 increase in BMI, the risk of cancer increased by 10%. Even obesity during childhood or adolescence can increase the risk, though the data is less clear due to the significant potential for recall bias [28,29]. Subjects with metabolic syndrome, which includes obesity, diabetes, and pulmonary disease, are at a higher risk for advanced neoplasms found during colonoscopy [30].…”