Pre-diagnostic body mass index and weight change in relation to colorectal cancer survival among incident cases from a population-based cohort study.

Ida Laake,Randi Selmer,Marit B Veierød,Inger Thune,Inger K Larsen

doi:10.1186/s12885-016-2445-4

Abstract

BackgroundWhether excess body weight influences colorectal cancer (CRC) survival is unclear. We studied pre-diagnostic body mass index (BMI) and weight change in relation to CRC-specific mortality among incident CRC cases within a large, Norwegian cohort.MethodsParticipants’ weight was measured at health examinations up to three times between 1974 and 1988. CRC cases were identified through linkage with the Norwegian Cancer Registry. In total, 1336 men and 1180 women with a weight measurement >3 years prior to diagnosis were included in analyses. Hazard ratios (HRs) and confidence intervals (CIs) were estimated with Cox regression.ResultsDuring a mean follow-up of 5.8 years, 507 men and 432 women died from CRC. Obesity (BMI ≥30 kg/m2) was associated with higher CRC-specific mortality than normal weight (BMI 18.5–25 kg/m2) in men with proximal colon cancer, HR = 1.85 (95 % CI 1.08–3.16) and in women with rectal cancer, HR = 1.93 (95 % CI 1.13–3.30). Weight gain was associated with higher CRC-specific mortality in women with CRC, colon cancer, and distal colon cancer, HRs per 5 kg weight gain were 1.18 (95 % CI 1.01–1.37), 1.22 (95 % CI 1.02–1.45), and 1.40 (95 % CI 1.01–1.95), respectively. Weight gain was not significantly associated with survival in men.ConclusionsMaintaining a healthy weight may benefit CRC survival, at least in women.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2445-4) contains supplementary material, which is available to authorized users.

Highlights

Whether excess body weight influences colorectal cancer (CRC) survival is unclear
Some studies have evaluated the association between body mass index (BMI) at the time of treatment, i.e. around the time of diagnosis, and survival after colon [5,6,7] or rectal cancer [8, 9], but the results are difficult to interpret since weight loss is a clinical feature of CRC [10]
For CRC, we examined whether the association between weight gain and mortality differed with initial BMI (

Summary

Introduction

Whether excess body weight influences colorectal cancer (CRC) survival is unclear. We studied pre-diagnostic body mass index (BMI) and weight change in relation to CRC-specific mortality among incident CRC cases within a large, Norwegian cohort. Excess body weight is an established risk factor for colorectal cancer (CRC) in both men and women, and a positive association between body mass index (BMI) and CRC incidence has been found in numerous studies [1]. It is possible that the mechanisms linking excess body weight to development of CRC tumors, related to e.g. insulin, insulin-like growth factors, inflammation, and steroid hormones, influence tumor progression and thereby survival of the disease [3, 4].

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