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

Abstract

General obesity, typically measured using body mass index (BMI), has been associated with an increased risk of several cancers. However, few prospective studies have been conducted in Asian populations. Although central obesity, often measured using waist-hip ratio (WHR), is more predictive for type 2 diabetes and cardiovascular diseases (CVD) risk than BMI, knowledge of its association with cancer incidence is limited. In a cohort of 68, 253 eligible Chinese women, we prospectively investigated the association of BMI, WHR, and weight change during adulthood with risk of overall cancer and major site-specific cancers using multivariate Cox proportional hazard models. Compared to the BMI group of 18.5-22.9 kg/m2, obese (BMI≥30 kg/m2) women were at an increased risk of developing overall cancer (hazard ratio = 1.36, 95% confidence interval = 1.21-1.52), postmenopausal breast cancer (HR: 2.43, 95% CI: 1.73-3.40), endometrial cancer (HR: 5.34, 95% CI: 3.48-8.18), liver cancer (HR: 1.93, 95% CI: 1.14-3.27), and epithelial ovarian cancer (HR: 2.44, 95% CI: 1.37-4.35). Weight gain during adulthood (per 5 kg gain) was associated with increased risk of all cancers combined (HR: 1.05, 95% CI: 1.03-1.08), postmenopausal breast cancer (HR: 1.17, 95% CI: 1.10-1.24), and endometrial cancer (HR: 1.37, 95% CI: 1.27-1.48). On the other hand, WHR was not associated with cancer risk after adjustment for baseline BMI. These findings suggest that obesity may be associated with cancer risk through different mechanisms from those for type 2 diabetes and CVD and support measures of maintaining health body weight to reduce cancer risk in Chinese women.

Abdominal Obesity and Gastroesophageal Cancer Risk: Systematic Review and Meta-Analysis of Prospective Studies

“…Furthermore, six studies [36][37][38][39][40][41] were excluded because the risk estimate for the association of interest was not available. Finally, seven prospective cohort studies [24][25][26][27][28][29] -one publication [28] included two separate cohorts -from six publications were included in the final analysis. The characteristics of the included studies are summarised and listed in Table 1.…”

“…A total of 2130 gastroesophageal cancer cases were diagnosed amongst 913182 participants. Two prospective cohort studies were conducted in the United States [25,26] and Norway [28], and one each in Australia [24], multiple European countries [27], and China [29]. Regarding the sex of the participants, one study [29] evaluated only women and the remaining six [24][25][26][27][28] included both sexes.…”

“…In analysis restricted to studies that adjusted for BMI [25,27,29], higher WHR was positively associated with GC (RR: 1.40, 95% CI: 1.08, 1.82; I 2 =36%, P=0.181), whereas no association was found with esophageal cancer (RR: 2.30, 95% CI: 0.86, 6.17; I 2 =80.5%, P=0.024). The sensitivity analyses omitting one study at a time and calculating the combined RRs for the remaining studies showed that the combined RRs was not substantially affected by any single study.…”

“…Five prospective cohort studies [24][25][26][27]29] Figure 5). In analysis restricted to studies that adjusted for BMI [25,27,29], higher WHR was positively associated with GC (RR: 1.40, 95% CI: 1.08, 1.82; I 2 =36%, P=0.181), whereas no association was found with esophageal cancer (RR: 2.30, 95% CI: 0.86, 6.17; I 2 =80.5%, P=0.024).…”

“…In addition, intra-abdominal fat has been hypothesised to be biologically different from fat in other areas with regard to tumor angiogenesis and cell proliferation [22,23]. Although general obesity has emerged as a potential risk factor for gastroesophageal cancer, but the association between abdominal obesity and gastroesophageal cancer is still poorly understood, partly because of sparse evidence from prospective studies available at that time, which limited the strength of the conclusions [24][25][26][27][28][29]. Given these considerations, providing clear evidence regarding potentially detrimental effect of abdominal obesity on gastroesophageal cancer would be important for clinical interventions, including weight loss program or weight management program and gastroesophageal cancer screening guidelines for obese individuals.…”