A 30-year survey of drug use in the 1914 birth cohort in Glostrup County, Denmark: 1964–1994

Background and aims: Use of drugs increases with age. Several drugs as well as multiple drug intake are recognized risk factors for symptoms, disability, hospitalizations, and even mortality, due to side effects and problems with compliance. Yet, little is known about the long-term effects. As a first step, this longitudinal study of a general population gives insight into consumption patterns including multiple drug intake (“polypharmacy”) and individual adherence to drug use over a 30-year period. Methods: This is a study based on the first large longitudinal population study of the health of adult Danes. Examinations were performed at 50, 60, 70 and 80 years of age. The Statistical Package for the Social Sciences (SPSS) was used to check participants’ individual adherence to each of six main drug categories, calculated stepwise. Results: 802 persons were included at 50 years of age in 1964. Of these, 213 were still participating in the study in 1994. The general use of drugs increased for all drug categories with age. Women used statistically significantly more drugs than men and showed a higher degree of polypharmacy. The individual adherence to antihypertensives was greater than the corresponding adherences to analgesics, psychoactive drugs, or hypnotics. At least two-thirds of all remaining initial users of antihypertensives still took them at 80 years of age. For other drug categories, the corresponding values were half or less. Conclusions: For the initial population studied over a period of 30 years, the use of drugs increased with age, but the drugs were not prescribed for the same people over time. During the 30-year period, individual patients’ drug adherence habits were in accordance with scientific evidence: patients adhered to long-term use of antihypertensive drugs, but used analgesics, psychoactive drugs and hypnotics for only shorter periods.