Effect of body mass index and alcohol consumption on liver disease: analysis of data from two prospective cohort studies
・１週間当たりの飲酒が15単位以上では、肝疾患による死亡率の相対危険度は、通常または痩せている人で3.16 (95% confidence interval 1.28 to 7.8) 倍、体重オーバーの人で7.01 (3.02 to 16.3) 倍、肥満の人で、18.9 (6.84 to 52.4)倍。ちなみに、１週間当たり1-14 単位の飲酒で、肥満の人の相対危険度は、5.3 (1.36 to 20.7)倍。
Objective To investigate whether alcohol consumption and raised body mass index (BMI) act together to increase risk of liver disease.
Design Analysis of data from prospective cohort studies.
Participants Data were from two of the Midspan prospective cohort studies (9559 men): "Main" study 1965-8, participants from workplaces across central belt of Scotland, population of island of Tiree, and mainland relatives, and "Collaborative" study, 1970-3, participants from 27 workplaces in Glasgow, Clydebank, and Grangemouth. Follow-up was to 31 December 2007 (median 29 years, range 0.13-42). We divided participants into nine groups based on measures of body mass index (BMI) (underweight/normal weight <25, overweight 25 to <30, and obese 30) and alcohol consumption (none, 1-14, and 15 units per week).
Main outcome measures Liver disease morbidity and mortality.
Results 80 (0.8%) men died with liver disease as the main cause and 146 (1.5%) with liver disease as any cause. In the Collaborative study, 196 men (3.3%) had liver disease defined by a death, admission, or cancer registration. BMI and alcohol consumption were strongly associated with liver disease mortality in analyses adjusted for other confounders (P=0.001 and P<0.0001 respectively). Drinkers of 15 or more units per week in any BMI category and obese drinkers had raised relative rates for all definitions of liver disease, compared with underweight/normal weight non-drinkers. Drinkers of 15 or more units per week had adjusted relative rates for liver disease mortality of 3.16 (95% confidence interval 1.28 to 7.8) for underweight/normal weight men, 7.01 (3.02 to 16.3) for overweight, and 18.9 (6.84 to 52.4) for obese men. The relative rate for obese men who consumed 1-14 units per week was 5.3 (1.36 to 20.7). The relative excess risk due to interaction between BMI and alcohol consumption was 5.58 (1.09 to 10
.1); synergy index=2.89 (1.29 to 6.47).
Conclusions Raised BMI and alcohol consumption are both related to liver disease, with evidence of a supra-additive interaction between the two. The occurrence of both factors in the same populations should inform health promotion and public health policies.