Co- and multimorbidity patterns in an unselected Norwegian population: cross-sectional analysis based on the HUNT Study and theoretical reflections concerning basic medical models

Abstract

Rationale and aims: Accumulating evidence shows that diseases tend to cluster in diseased individuals, so-called multimorbidity. The aim of this study was to analyze multimorbidity patterns, empirically and theoretically, to better understand the phenomenon. Population and methods: The Norwegian population-based Nord-Trøndelag Health Study HUNT 3 (2006-8), with 47,959 individuals aged 20-79 years. A total of 21 relevant, longstanding diseases/malfunctions were eligible for counting in each participant. Multimorbidity was defined as two or more chronic conditions.Results: Multimorbidity was found in 18% of individuals aged 20 years. The prevalence increased with age in both sexes. The overall age-standardized prevalence was 42% (39% for men, 46% for women). ‘Musculoskeletal disorders’ was the disease-group most frequently associated with multimorbidity. Three conditions, strategically selected to represent different diagnostic domains according to biomedical tradition; gastro-esophageal reflux, thyroid disease and dental problems, were all associated with both mental and somatic comorbid conditions. Conclusions and implications: Multimorbidity appears to be prevalent in both genders and across age-groups, even in the affluent and relatively equitable Norwegian society. The disease clusters typically transcend biomedicine’s traditional demarcations between mental and somatic diseases and between diagnostic categories within each of these domains. A new theoretical approach to disease development and recovery is warranted, in order to adequately tackle ‘the challenge of multimorbidity’, both empirically and clinically. We think the concept allostatic load can be systematically developed to “capture” the interrelatedness of biography and biology and to address the fundamental significance of “that, which gains” versus “that, which drains” any given human being.