Original ArticleClinical and lifestyle-related risk factors for incident multimorbidity: 10-year follow-up of Finnish population-based cohorts 1982–2012
Introduction
Aging of the population will be a huge challenge for European countries during upcoming decades. It is well-known that the incidence of many chronic diseases, such as type 2 diabetes mellitus (DM), cardiovascular diseases (CVD) and cancer, increases by age and as a consequence the number of affected people rises [1]. Furthermore, as diseases tend to cluster, increasing numbers of people are found to have multiple diseases or medical conditions at the same time, a phenomenon which is called multimorbidity [2].
Multimorbidity affects more than half of the elderly population and its impact on the burden to individuals and societies is considerable. It is connected with disability and functional decline, poor quality of life and greater use of health services, higher health care costs, and premature mortality [3]. Studies have shown that in addition to age, multimorbidity is associated with female gender and lower education [3], [4].
Only a few studies have evaluated the association of modifiable risk factors with multimorbidity, and especially the longitudinal studies are scarce [5], [6], [7], [8], [9]. Biological and lifestyle factors such as hypercholesterolemia, hypertension, obesity, smoking, physical inactivity and unhealthy diet are common risk factors for many chronic diseases [1]. Therefore, it is justified to assume that over time, the exposure to these risk factors can lead to multimorbidity, especially among people who already have one chronic disease. To make prevention of multimorbidity possible, better understanding on the predisposing factors of multimorbidity is warranted. In addition, affected people have typically been patients in the primary health care for several years before they become multimorbid. That would offer the “window of opportunity” for primary prevention of multimorbidity, by recognition and better management of its risk factors.
Finland has a very strong history in risk factor monitoring and prevention of chronic diseases [10]. The aim of this study was to investigate which baseline risk factors predispose to multimorbidity, defined by the time of the diagnosis of the “second” common chronic disease, during 10-year follow-up of population-based cohorts. The risk factors for multimorbidity were investigated separately for people without diagnosis of DM, CVD, asthma/chronic obstructive pulmonary disease (COPD), cancer or rheumatoid arthritis at baseline (referred to as initially disease-free) and also for people with either DM or CVD at baseline. DM and CVD were selected as “index diseases” because they are among the most common and costly chronic diseases on population level.
Section snippets
Study population
The study population comprised people who were randomly selected for the population-based FINRISK surveys in 1982, 1987, 1992, 1997 and 2002 in five areas of Finland (North Karelia, Northern Savo, cities of Turku and Loimaa, cities of Helsinki and Vantaa and Oulu province). Detailed descriptions of the National FINRISK Study methodology have been published previously [11]. The common age range for all surveys was 25 to 64 years and for this age group the total sample size for all surveys was
Baseline characteristics of study population
The combined cohort included 15,904 men and 17,068 women (Table 1). Of men, 14,923 (93.8%) and of women, 16,284 (95.4%) were initially disease-free, 586 (3.7%) and 663 (3.9%) had DM and 395 (2.5%) and 121 (0.7%) had CVD, respectively. Men and women with DM or CVD were significantly older than disease-free individuals, and had higher systolic blood pressure and BMI. Men and women with DM were more often physically inactive and diabetic women had also higher cholesterol values compared with
Discussion
We did a register-based study, where we investigated the baseline risk factors predisposing to incident multimorbidity within population-based cohorts. We focused our analyses on the combinations of chronic conditions with the highest incidence (DM, CVD, asthma/COPD, cancer and rheumatoid arthritis) on population level. Furthermore, we stratified the analyses to initially disease-free people, people with diagnosed DM at baseline, and people with diagnosed CVD at baseline. DM and CVD were
Learning points
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Smoking, obesity, and physical inactivity were risk factors for multimorbidity among initially disease-free men and women.
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In people with DM at baseline, the factors increasing the risk of incident multimorbidity were smoking, physical inactivity, and hypertension in men and BMI and smoking in women.
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In people with CVD at baseline, the factors increasing the risk of incident multimorbidity were physical inactivity in men and low fruit and vegetable consumption in men and women.
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More attention
Conflict of interests
None declared.
Acknowledgments
This publication arises from the Joint Action CHRODIS, which has received funding from the European Union (grant number 2013 22 01), in the framework of the Health Programme (2008-2013). Sole responsibility lies with the author and the Consumers, Health, Agriculture and Food Executive Agency is not responsible for any use that may be made of the information contained therein. The data for the analyses were provided by the National Institute for Health and Welfare, Finland.
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