High BMI Linked to Multiple Cancer Risk
Obesity drives the incidence of cancer in the UK population
- Date: 15 Aug 2014
- Author: Lynda Williams, Senior medwireNews Reporter
- Topic: Cancer Aetiology, Epidemiology, Prevention
medwireNews: Research published in The Lancet reveals the impact of obesity on the incidence of cancer, with 17 of the 22 most common malignancies found to be significantly associated with body mass index (BMI).
The study of 5.24 million UK individuals in the Clinical Practice Research Datalink, including 166,955 with cancer diagnoses, revealed significant variation in the impact of obesity on cancer, report Krishnan Bhaskaran, from London School of Hygiene and Tropical Medicine in London, UK, and co-authors.
Each 5 kg/m2 increase in BMI was most strongly associated with a linear increase in uterine cancer (hazard ratio [HR]=1.62), after adjusting for age, calendar year, gender, menopausal status, diabetes, socioeconomic status, alcohol use and smoking status.
This was followed by cancers of the gallbladder (HR=1.31), kidney (HR=1.25), cervix (HR=1.10) and thyroid gland (HR=1.09) and leukaemia (HR=1.09). There was also a significant and positive association for cancers of the liver (HR=1.19), colon (HR=1.10) and ovary (HR=1.09) and postmenopausal breast cancer (HR=1.05).
The researchers also identified inverse associations between BMI and the risk of prostate cancer (HR=0.96), premenopausal breast cancer (HR=0.89), oral cavity malignancy (HR=0.81) and lung cancer (HR=0.82)
When analysis was restricted to non-smokers, however, only the modest inverse associations between BMI and prostate cancer and premenopausal breast cancer remained.
Low BMI was associated with an increased risk of lung, oral cavity and stomach cancers for smokers and former smokers but not non-smokers, the team explains.
“Assuming the relationships to be causal, many cancers are attributable to overweight and obesity”, the researchers write, estimating that up to 41% of uterine and at least 10% of gallbladder, kidney, liver and colon malignancies may be associated with an obese BMI (≥30 kg/m2).
Noting that increasing BMI was associated with some cancers even when the BMI was within a healthy range, the team estimates that a 1 kg/m2 increase in BMI across the UK population would translate to an additional 3790 annual cancer diagnoses of the 10 cancers with the strongest association.
“Our data strengthen the rationale to assess and implement strategies aimed at stopping these trends and mitigating their public health effects”, emphasise Krishnan Bhaskaran et al.
In an accompanying comment, Peter Campbell, from the American Cancer Society in Atlanta, Georgia, USA, says the analytical tools used and the concurrence with findings from previous reports provide confidence in the study’s results.
“Research strategies that identify population-wide or community-based interventions and policies that effectively reduce overweight and obesity should be particularly encouraged and supported”, he recommends.
“Moreover, we need a political environment, and politicians with sufficient courage, to implement such policies effectively.”
Bhaskaran K, Douglas I, Forbes H, et al. Body-mass index and risk of 22 specific cancers: a population-based cohort study of 5.24 million UK adults. Lancet 2014; Early online publication 14 August. doi:10.1016/S0140-6736(14)60892-8
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