A prospective study of weight change and systemic inflammation over 9 y.

Background: An increase in weight is a risk factor for cardiovascular disease and cancer. This increased risk may be mediated by inflammation, but no long-term data are available on the effect of weight gain on systemic inflammation.

Objective: We tested the hypothesis that weight gain is associated with an increase in systemic inflammation during a 9-y period.

Design: In 1991 data on body weight and a blood sample were collected from a random sample of 2425 randomly selected adults from a community-based cohort in Nottingham, United Kingdom. In 2000, these measures were repeated in 1301 of these participants. The main outcome measure was change in systemic inflammation as measured by serum C-reactive protein (CRP) from the 1222 participants who provided paired samples.

Results: The mean change in weight from 1991 to 2000 was 2.9 kg (95% CI: 2.6, 3.2 kg). The geometric mean of CRP in 1991 was 1.22 mg/L (95% CI: 0.03, 125.0 mg/L), and it increased to 1.76 mg/L (95% CI: 0.09, 62.0 mg/L) in 2000 (P<0.001). A linear association was observed between increase in weight and serum CRP, with a 1-kg increment in weight being associated with an additional increase in CRP of 0.09 mg/L (95% CI: 0.02, 0.16 mg/L) during this time period.

Conclusion: During a 9-y period, an increase in weight is associated with an increase in systemic inflammation. This provides a mechanism that may explain some of the previously reported association of weight gain with an increased risk of both cancer and cardiovascular disease.