Interaction between cardiovascular risk factors and body mass index and 10-year incidence of cardiovascular disease, cancer death, and overall mortality

The effect of above-normal body mass index (BMI) on health outcomes is controversial because it is difficult to distinguish from the effect due to BMI-associated cardiovascular risk factors. The objective was to analyze the impact on 10-year incidence of cardiovascular disease, cancer deaths and overall mortality of the interaction between cardiovascular risk factors and BMI. We conducted a pooled analysis of individual data from 12 Spanish population cohorts with 10-year follow-up. Participants had no previous history of cardiovascular diseases and were 35-79 years old at basal examination. Body mass index was measured at baseline being the outcome measures ten-year cardiovascular disease, cancer and overall mortality. Multivariable analyses were adjusted for potential confounders, considering the significant interactions with cardiovascular risk factors. We included 54,446 individuals (46.5% with overweight and 27.8% with obesity). After considering the significant interactions, the 10-year risk of cardiovascular disease was significantly increased in women with overweight and obesity [Hazard Ratio = 2.34 (95% confidence interval: 1.19-4.61) and 5.65 (1.54-20.73), respectively]. Overweight and obesity significantly increased the risk of cancer death in women [3.98 (1.53-10.37) and 11.61 (1.93-69.72)]. Finally, obese men had an increased risk of cancer death and overall mortality [1.62 (1.03-2.54) and 1.34 (1.01-1.76), respectively]. In conclusion, overweight and obesity significantly increased the risk of cancer death and of fatal and non-fatal cardiovascular disease in women; whereas obese men had a significantly higher risk of death for all causes and for cancer. Cardiovascular risk factors may act as effect modifiers in these associations.