Study Finds That Traditional Risk Factors Don’t Fully Explain Accumulation of Chronic Diseases

As populations age worldwide, the phenomenon of multimorbidity—where individuals develop multiple chronic illnesses simultaneously—becomes increasingly prevalent. Traditionally, research has concentrated on specific risk factors and their direct link to individual diseases. However, a recent comprehensive study has demonstrated that known risk factors alone do not entirely account for the complex process of disease accumulation across multiple organ systems.

Published in The Lancet Healthy Longevity, the study analyzed data from a cohort of 2,000 individuals born between 1934 and 1944 in Helsinki. Researchers evaluated 22 risk factors spanning from birth to middle age, including early life factors such as birth weight and childhood growth, socio-economic status, lifestyle choices like smoking, alcohol consumption, physical activity, diet, alongside clinical measurements like body mass index, blood pressure, and blood glucose levels. The investigation also considered unmeasured or latent factors—such as air pollution, genetic influences, and environmental exposures—that could influence disease development.

Key findings revealed that both measured and latent factors together could explain up to 75% of the incidence of chronic diseases across various organ systems, including cardiovascular, metabolic, gastrointestinal, musculoskeletal, respiratory, neurological, psychiatric, and sensory organs. Notably, factors like age, BMI, hypertension, and hyperglycemia were significant contributors to disease onset, explaining a substantial portion of cases. Nevertheless, about 25% of disease cases remain attributable to unknown or unmeasured latent factors.

The study emphasizes that while individuals can influence their health by managing factors such as body weight, blood pressure, blood glucose, lifestyle behaviors, and diet, there is a critical need for public health policies that address these issues at a broader level. Additionally, the notable role of latent, unidentified risk factors underscores the importance of ongoing research to uncover new influences on disease development.

Understanding the complex interplay between known and unknown risk factors is crucial for developing more effective prevention strategies. Identifying and mitigating latent risk factors could significantly reduce the burden of chronic diseases in aging populations, making this an important area for future investigation.

For more details, see the original study: Markus J Haapanen et al, "Observed and hidden factors underlying the accumulation of chronic diseases across eight major organ systems: a longitudinal birth cohort study," The Lancet Healthy Longevity (2025).