Adiponectin is an adipocyte-derived
protein with an
insulin-sensitizing action. Circulating levels of
adiponectin are inversely correlated with
obesity, especially
abdominal obesity. Some studies have suggested that low levels of circulating
adiponectin might be related to increased risk of
colorectal cancer and
adenomas. The present study examined the relationship between total and high-molecular-weight (HMW)
adiponectin to colorectal
adenomas in the Self Defense Forces (SDF) Health Study. The study subjects comprised 656 cases of colorectal
adenomas and 648 controls with normal colonoscopy among men receiving a preretirement health examination at two Self Defense Forces hospitals. Total and HMW
adiponectin were slightly lower in
adenoma cases than in controls; geometric means of total
adiponectin were 5.42 microg/mL in cases and 5.63 microg/mL in controls (P = 0.13), and the corresponding values of HMW
adiponectin were 2.47 microg/mL and 2.57 microg/mL, respectively (P = 0.29). Regardless of adjustment for body mass index and other lifestyle factors, total
adiponectin was unrelated to the risk of colorectal
adenomas. Total
adiponectin levels were inversely related to the risk of large
adenomas (>or= 5 mm), but not of small
adenomas, with a nearly statistically significant decreasing trend (P = 0.06). However, the inverse association was largely ascribed to body mass index and other lifestyle factors. HMW
adiponectin showed no clear association with either overall or size-specific risk of colorectal
adenomas. The study provided suggestive evidence for a protective association between
adiponectin and large
adenomas, but did not indicate a protective association independent of adiposity.