Insomnia symptoms and subsequent cardiovascular medication: a register-linked follow-up study among middle-aged employees.

Sleep disturbances have been associated with an increased risk of cardiovascular disease outcomes. The associations of insomnia with hypertension and dyslipidaemia, the main modifiable cardiovascular risk factors, are less studied. We especially lack understanding on the longitudinal effects of insomnia on dyslipidaemia. We aimed to examine the associations of insomnia symptoms with subsequent prescribed medication for hypertension and dyslipidaemia using objective register-based follow-up data. Baseline questionnaire surveys among 40-60-year-old employees of the City of Helsinki, Finland, were conducted in 2000-2002 (n = 6477, response rate 67%, 78% women) and linked to a national register on prescribed reimbursed medication 5-7 years prior to and 5 years after baseline. Associations between the frequency of insomnia symptoms (difficulties in initiating and maintaining sleep, non-restorative sleep) and hypertension and dyslipidaemia medication during the follow-up were analysed using logistic regression analysis (odds ratios with 95% confidence intervals). Analyses were adjusted for pre-baseline medication, sociodemographic and work-related factors, health behaviours, mental health, and diabetes. Frequent insomnia symptoms were reported by 20%. During the 5-year follow-up, 32% had hypertension medication and 15% dyslipidaemia medication. Adjusting for age, gender and pre-baseline medication, frequent insomnia symptoms were associated with hypertension medication (odds ratio 1.57, 95% confidence interval 1.23-2.00) and dyslipidaemia medication (odds ratio 1.59, 95% confidence interval 1.19-2.12). Occasional insomnia symptoms were also associated with cardiovascular medication, though less strongly. Further adjustments had negligible effects. To conclude, insomnia should be taken into account in the prevention and management of cardiovascular disease and related risk factors.