Gjesdal Sturla, Lie Rolv T, Maeland John Gunnar
Division for Medical Statistics, Department of Public Health and Primary Health Care, University of Bergen, Norway.
Scand J Public Health. 2004;32(5):340-8. doi: 10.1080/14034940410029487.
A study was undertaken to investigate whether cohort or period effects could explain the varying and generally increasing incidence of disability pension in Norway between 1970 and 1999.
The study used data from a complete national register of new disability cases in Norway, including all cases of disability pension in the 16-60 age group categorized according to age and gender for each year from 1970 to 1999. The population at risk was defined for each year from census data and number of individuals already receiving disability pension. Data were organized in five-year age groups, five-year time periods and corresponding overlapping nine-year birth cohorts. Age- and gender-specific rates were displayed graphically for periods and cohorts. Separate Poisson regression models were fitted for age periods and age cohorts. Finally a combined age, period, and cohort model was applied.
The overall incidence was 7.4/1,000 non-disabled persons per year for women and 6.0/1,000 for men. For women 52.1% of the cases were in the 51-60 age group, whereas the corresponding figure for men was 57.6%. Statistical analysis showed an increasing trend for both genders, more pronounced for women than men. All time periods deviated significantly from the trend, either upwards or downwards. Age-cohort models showed less variation, but recent cohorts had higher than expected rates, especially for men.
Further studies should investigate why Norwegian women were more affected by the period effects than men. An increasing incidence of disability pension among recent cohorts is a major challenge for the Norwegian welfare system.
开展一项研究，以调查队列效应或时期效应是否能够解释1970年至1999年间挪威残疾抚恤金发病率的变化及总体上升趋势。
该研究使用了挪威新残疾病例完整国家登记册中的数据，包括1970年至1999年每年按年龄和性别分类的16至60岁年龄组的所有残疾抚恤金病例。根据人口普查数据和已领取残疾抚恤金的人数，为每年定义了风险人群。数据按五岁年龄组、五年时间段和相应重叠的九年出生队列进行整理。以图表形式展示了各时期和队列的年龄及性别特异性发病率。分别针对年龄时期和年龄队列拟合了泊松回归模型。最后应用了年龄、时期和队列的联合模型。
女性每年每1000名非残疾人员中的总体发病率为7.4，男性为6.0。女性52.1%的病例在51至60岁年龄组，而男性的相应比例为57.6%。统计分析表明，两性发病率均呈上升趋势，女性比男性更明显。所有时间段均显著偏离趋势，或上升或下降。年龄队列模型显示的变化较小，但最近的队列发病率高于预期，尤其是男性。
进一步的研究应调查为何挪威女性比男性更容易受到时期效应的影响。最近队列中残疾抚恤金发病率的上升对挪威福利体系构成了重大挑战。
