Low cholesterol, mortality, and quality of life in old age during a 39-year follow-up

Abstract

Objectives: We assessed the impact of serum cholesterol level in early midlife on total mortality during up to 39 years of follow-up and on the quality of life (QoL) in old age.

Background: Total effects of low serum cholesterol on health have been in dispute, especially in elderly persons, and there are few data on the long-term effects of low cholesterol on QoL.

Methods: The cohort consisted of 3,277 healthy businessmen age 30 to 45 years at baseline (1960s). In addition to baseline, serum cholesterol values were available for part of the cohort in 1974, 1986, and 2000. The QoL was assessed in 80.9% of survivors (n = 1,820, mean age 73 years) with a RAND-36 (SF-36) QoL questionnaire in 2000. Mortality up to 2002 (n = 1,173) was retrieved from national registers.

Results: Cholesterol was clearly reduced in survivors during follow-up, except in the lowest baseline serum cholesterol group. Baseline cholesterol predicted 39-year total mortality in a graded manner (p < 0.0001), and a value < or =5.0 mmol/l was associated with a 25% reduction in total mortality. In old age, the physical component summary score of RAND-36 was significantly (p = 0.02) higher (better) in the lowest baseline cholesterol group; no difference was found in the mental component summary score (p = 0.51).

Conclusions: Low serum cholesterol level in midlife predicted not only better survival but also better physical function and QoL in old age, without adversely affecting mental QoL.