Abstract
Repeated weight fluctuation has been proposed as a potential risk factor for increasing morbidity and mortality including cancer. We aimed to investigate the association between body weight variability (BWV) and all cancer and site-specific cancer incidence and the impact of smoking on these associations. A total of 1,759,848 cancer-free male subjects who had their weight measured at least 5 times from the National Health Insurance Service-Health Screening Cohort from 2002 to 2011 were included and followed up until 2015. BWV was defined as the average absolute difference between successive values (ASV). The risk of cancer and site-specific cancer from BWV was identified using Cox proportional hazards regression analysis using hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for potential confounders including weight, and stratified analysis was also conducted according to smoking status. During the 7,015,413 person-years of follow-up, 11,494 patients (0.65%) developed new-onset cancers. BWV was associated with a higher risk of all cancers after adjustment for confounders. The highest BWV quintile group compared to the lowest had greater risks of all cancers and site-specific cancers including lung, liver, and prostate cancer (HR 1.22, 95% CI 1.15–1.30; HR 1.22, 95% CI 1.07–1.39; HR 1.46, 95% CI 1.19–1.81; HR 1.36, 95% CI 1.15–1.62, in all cancers, lung, liver and prostate cancer, respectively). Due to small number of cancer occurrence, the risk of kidney cancer was increased, but statistically insignificant (HR 1.38, 95% CI 0.91–2.10). Similar results were observed in noncurrent smokers. However, in current smokers, the risks of all cancers and only prostate cancer were significantly increased in the highest BWV quintile group (HR 1.19, 95% CI 1.09–1.31; HR 1.51, 95% CI 1.08–2.11). The risk of kidney cancer also increased in this group, although the finding was not statistically significant (HR 1.77, 95% CI 0.87–3.63) This study suggested BWV is an independent risk factor for cancer in men, especially in lung, liver, and prostate cancer, but evidence was weaker in kidney cancer. This association remained significant only in prostate cancer in current smokers.
Highlights
Obesity has known as a risk factor for hypertension, diabetes, cardiovascular disease, and c ancer[1,2,3,4]
Sensitivity analyses were conducted by adjusting for initial BMI or initial weight instead of the mean weight and showed similar results. In this retrospective population-based longitudinal study, we found that strong evidence of the effect of body weight variability (BWV) on the risk of cancer incidence in men, in lung, liver, and prostate cancer
Many studies have been conducted on weight and cancer risk or weight gain and obesity-related cancer risk, whereas several studies have examined the association between BWV and cancer[11,13,20,21,22,23,24]
Summary
Obesity has known as a risk factor for hypertension, diabetes, cardiovascular disease, and c ancer[1,2,3,4]. Repeated weight fluctuation and weight cycling have been documented as risk factors for increasing morbidity and mortality, including c ancer[8]. Since the 1990s, several studies have reported that weight changes affect an increased cancer incidence, such as renal cell c ancer[9], and obesity-related cancers, including breast cancer, endometrial cancer, and colorectal c ancer[5,10,11,12,13]. According to the World Cancer Report released by the World Health Organization (WHO) in 2018, cancer is the second leading cause of mortality worldwide and was responsible for an estimated 9.6 million deaths in 2018 and globally approximately 1 in 6 deaths (Fact sheets on cancer, WHO). In Korea, a few studies have demonstrated that frequent weight change affects the development of papillary thyroid c ancer[14,15]
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