Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands ; National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
PLoS One. 2013 Sep 20;8(9):e74294. doi: 10.1371/journal.pone.0074294. eCollection 2013.
Disability-Adjusted Life Years (DALYs) have the advantage that effects on total health instead of on a specific disease incidence or mortality can be estimated. Our aim was to address several methodological points related to the computation of DALYs at an individual level in a follow-up study.
DALYs were computed for 33,507 men and women aged 20-70 years when participating in the EPIC-NL study in 1993-7. DALYs are the sum of the Years Lost due to Disability (YLD) and the Years of Life Lost (YLL) due to premature mortality. Premature mortality was defined as death before the estimated date of individual Life Expectancy (LE). Different methods to compute LE were compared as well as the effect of different follow-up periods using a two-part model estimating the effect of smoking status on health as an example.
During a mean follow-up of 12.4 years, there were 69,245 DALYs due to years lived with a disease or premature death. Current-smokers had lost 1.28 healthy years of their life (1.28 DALYs 95%CI 1.10; 1.46) compared to never-smokers. The outcome varied depending on the method used for estimating LE, completeness of disease and mortality ascertainment and notably the percentage of extinction (duration of follow-up) of the cohort.
We conclude that the use of DALYs in a cohort study is an appropriate way to assess total disease burden in relation to a determinant. The outcome is sensitive to the LE calculation method and the follow-up duration of the cohort.
残疾调整生命年（DALYs）的优势在于可以估计对总健康的影响，而不是对特定疾病发病率或死亡率的影响。我们的目的是在一项后续研究中解决与个体水平 DALYs 计算相关的几个方法学问题。
在 1993-7 年参加 EPIC-NL 研究的 33507 名 20-70 岁的男性和女性中计算了 DALYs。DALYs 是由于残疾而失去的年数（YLD）和由于过早死亡而失去的年数（YLL）的总和。过早死亡被定义为在个人预期寿命（LE）估计日期之前死亡。比较了不同的 LE 计算方法，并使用两部分模型估计了吸烟状况对健康的影响，该模型比较了不同的随访期的效果，作为示例。
在平均 12.4 年的随访期间，由于疾病或过早死亡而导致的 DALYs 有 69245 年。与从不吸烟者相比，当前吸烟者失去了 1.28 年的健康生命（1.28 DALYs 95%CI 1.10; 1.46）。结果因 LE 估计方法、疾病和死亡率的完整性以及队列的灭绝（随访时间）百分比而异。
我们得出结论，在队列研究中使用 DALYs 是评估与决定因素相关的总疾病负担的一种适当方法。结果对 LE 计算方法和队列的随访时间敏感。
