Background:
Literature has suggested that smoking is causally associated with insulin resistance and type 2 diabetes. The smoking-diabetes association is often believed to be mediated by abdominal obesity. However, literature is scarce concerning whether smoking is related to visceral adipose tissue (VAT) beyond body mass and other lifestyle factors that influence abdominal fatness. We examined whether lifetime cigarette smoking is independently associated with VAT among Japanese men.
Method:
We cross-sectionally investigated community-based samples of Japanese men recruited from Shiga, Japan from 2006 to 2008, aged 40 to 64 years and free of cardiovascular disease. Areas of VAT and subcutaneous adipose tissues (SAT) were calculated upon a computer tomography image taken at the level of participant’s L
4-5
. Adipose tissue was defined as -190 to -30 Hounsfield Unit. Amount of cigarette smoking was assessed using structured self-administered questionnaire, and quantified as Brinkman Index (BI, the number of cigarettes smoked per day multiplied by the number of years of smoking). Using linear regression, we calculated adjusted means of abdominal obesity indices (VAT, SAT, VAT-SAT ratio [VSR], and waist-hip ratio [WHR]) according to tertiles. Adjusting covariates included age, education, body mass index (BMI), physical activity at workplace, and drinking.
Results:
533 men were studied (mean age 56.1 years; 40.1% for current-, 43.5% for former-smoker). Average BMI, VAT, SAT, and VSR were 23.8 kg/m
2
, 117 (cm
2
),122 (cm
2
), and 1.01. Although significant associations between smoking and VAT and SAT were absent, VSR increased significantly with increasing BI (
p
=0.02) independent of BMI and other covariates (Table).
Conclusion:
In Japanese men, cigarette smoking is adversely associated with a rise in the faction of visceral to subcutaneous adipose tissue independent of BMI and other lifestyle factors. Visceral fat may, in part, mediate the smoking-diabetes association.
Characteristics and Cluster of Lifestyle Factors in Neurological Outpatients
