To evaluate the effect of diabetes onset on health-related quality of life (HRQoL) in men.

A prospective cohort study with a 34-year follow-up (The Helsinki Businessmen Study, Finland). A socio-economically homogenous group of 1815 men (born 1919–1934), free of diabetes and clinically healthy in 1974, when cardiovascular risk factors were measured and self-related health (SRH) evaluated with a five-step scale. In 2000 and 2007, HRQoL was assessed with a questionnaire, including the RAND-36 (SF-36) instrument. Incidence of diabetes up to 2007 was retrieved using the National Reimbursement Register for diabetes medication, or from questionnaire surveys between 2000 and 2007. Onset of diabetes was divided as follows: 1991 or earlier, 1992–1995, 1996–2000, 2001–2003, 2004–2007.

Altogether 216 men (11.9%) developed diabetes during the 34-year follow-up, and they had more cardiovascular risk factors at baseline than those without diabetes. According to the evaluation in 2000, and compared to men free of diabetes during follow-up, three RAND-36 scales (physical function, general health, social functioning) were significantly worsened already after 0–4years from diabetes onset and did not deteriorate thereafter. Instead, HRQoL was not worsened up to 7years before diabetes onset (between 2000 and 2007). No consistent impact of diabetes was observed on mental health-related scales.

Diabetes does not affect physical health-related quality of life until after diabetes onset. Lack of an association between the prediabetic state and HRQoL may offer an important window for the prevention and argument for early detection also from the HRQoL viewpoint.