The Association between Obesity and Cancer Risk: A Meta-Analysis of Observational Studies from 1985 to 2011

Area of Science:

• Oncology
• Epidemiology
• Public Health

Background:

• Cancer and cardiovascular diseases are leading global causes of death.
• Obesity is a significant risk factor for numerous cancers.
• Previous research has identified a link between obesity and 13 specific cancers.

Purpose of the Study:

• To synthesize existing evidence on the association between obesity and 13 specific cancers.
• To evaluate the strength and significance of the obesity-cancer relationship.
• To provide data for public health strategies aimed at cancer prevention.

Main Methods:

• Systematic review and meta-analysis of previously identified and newly searched studies (Medline, Embase) from January 2007 to May 2011.
• Independent relevance and quality assessment by two reviewers.
• Random effects meta-analysis performed separately for men and women.

Main Results:

• Included 98 studies from 18 countries (1985-2011); analyzed 57 high/moderate quality studies.
• Obese men showed higher risk for colon, renal, gallbladder, pancreatic, and malignant melanoma.
• Obese women had increased risk for esophageal adenocarcinoma, endometrial, gallbladder, renal, pancreatic, leukemia, postmenopausal breast, and colon cancers.

Conclusions:

• A significant positive association exists between obesity and cancer incidence.
• The strength of the association varies by cancer type and sex.
• Reducing obesity rates could lead to substantial cancer prevention, particularly in populations with high obesity prevalence like Canada.