School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region.
Prev Med. 2013 Feb;56(2):118-23. doi: 10.1016/j.ypmed.2012.11.017. Epub 2012 Dec 4.
Obesity was not identified as a risk factor for influenza until the recent 2009 H1N1 pandemic. Based on a cohort of 66,820 subjects aged 65 years and over with the follow-up period from July 1998 to December 2010 in Hong Kong, we assessed the modifying effect of obesity on mortality risks specifically attributable to influenza infections (termed as "influenza associated mortality risks").
A Cox proportional model with time dependent covariates was adopted to assess the hazard ratio of mortality in each obesity group when influenza activity increased 10% in the community.
Hazard ratio of influenza-associated all-cause mortality was 1.081 (95% confidence interval 1.013, 1.154), 1.047 (1.012, 1.084), 0.981 (0.936, 1.028), 1.018 (0.980, 1.058) and 1.062 (0.972, 1.162) in the underweight, normal, overweight, moderate obesity and severe obesity groups, respectively. A similar U shape pattern across the obesity groups was also observed in influenza associated mortality risks of respiratory diseases, pneumonia and influenza. This pattern was more evident among ever smokers, although the influenza effect estimates in each obesity group had overlapping confidence intervals.
There is some but limited evidence to suggest that underweight and obesity were associated with higher mortality risks of influenza in old population.
直到最近的 2009 年 H1N1 大流行，肥胖才被确定为流感的一个危险因素。本研究基于香港一个年龄在 65 岁及以上的队列，共 66820 名受试者，随访时间从 1998 年 7 月至 2010 年 12 月，评估了肥胖对流感感染（称为“流感相关死亡风险”）特异性死亡率的影响。
采用时依协变量 Cox 比例模型来评估当社区中流感活动增加 10%时，每个肥胖组的死亡率风险比。
流感相关全因死亡率的风险比分别为 1.081（95%置信区间 1.013，1.154）、1.047（1.012，1.084）、0.981（0.936，1.028）、1.018（0.980，1.058）和 1.062（0.972，1.162），分别在体重不足、正常、超重、中度肥胖和重度肥胖组。在呼吸道疾病、肺炎和流感的流感相关死亡风险中，肥胖组之间也观察到类似的 U 形模式。这种模式在既往吸烟者中更为明显，尽管在每个肥胖组中的流感效应估计值有重叠的置信区间。
有一些但有限的证据表明，消瘦和肥胖与老年人群流感死亡率升高有关。
