Multimorbidity and health related quality of life in midlife – a longitudinal study from Northern Finland Birth Cohort 1966

Multimorbidity is a major public health concern. According to previous studies, multimorbidity has been shown to be associated with health-related quality of life (HRQoL). However, existing data concerning high income countries are mainly based on cross-sectional studies. Consequently, longitudinal investigations have been called for. There exist several definitions of multimorbidity in previous population studies, and usually definition is based on self-reported symptoms or diseases or included only few diagnoses. This study aimed to examine how the number of doctor-diagnosed chronic diseases influences HRQoL over time in a population-based setting. At 31 and 46 years, participants (n = 3573) of the Northern Finland Birth Cohort 1966 answered 15-Dimensional HRQoL questionnaire (15D). Mean 15D-Scores (varies between 0 and 1) were counted according to the number of 43 chosen chronic diseases. These diseases were found and the definition of multimorbidity was measured by a method using both self-reported doctor-diagnosed and register-based chronic diseases. In both genders, the mean difference of 15D-Scores increased monotonously in line with the increasing number of new emerging diseases diagnosed for 15 years of follow-up from the age of 31–46 years (p In general, HRQoL decreased during 15-year follow-up for everyone. Furthermore, decrease in the quality of life is significantly associated with multimorbidity in this longitudinal setting.

共病（Multimorbidity）是重大公共卫生关切议题。既往研究证实，共病与健康相关生命质量（health-related quality of life, HRQoL）存在显著关联。然而，当前高收入国家的相关研究数据多基于横断面研究，因此学界呼吁开展纵向调查。
既往人群研究中，共病的定义存在多种标准，通常以自我报告的症状或疾病为依据，或仅纳入少量诊断条目。本研究旨在基于人群队列，探讨医生确诊的慢性疾病数量随时间推移对健康相关生命质量的影响。
芬兰北部1966年出生队列（Northern Finland Birth Cohort 1966）的3573名参与者，分别在31岁和46岁时完成了15维度健康相关生命质量问卷（15D）。研究人员依据43种选定慢性疾病的患病数量，计算了平均15D评分（评分取值范围为0至1）。该研究对疾病的确认及共病的定义，采用了结合自我报告医生确诊疾病与登记在册慢性疾病的综合方法。
在男女两个性别群体中，从31岁至46岁的15年随访期间，随随访期内新确诊疾病数量的增加，15D评分的平均差值呈单调递增趋势（原文此处p值标注存在疏漏）。总体而言，所有参与者在15年随访期间的健康相关生命质量均出现下降。此外，在该纵向研究场景中，生命质量的下降与共病存在显著关联。