Finnish study links evening chronotype to higher disability pension risk
Finnish researchers followed 5,679 adults for 12 years and found that people who naturally stay up late and wake late were granted disability pensions more often than morning types. The gap was roughly 70%.
Researchers in Finland have found that people with an evening chronotype, commonly called "night owls", face a considerably higher risk of losing their ability to work and receiving a disability pension than morning types, or "larks". The study was published in the journal Occupational & Environmental Medicine. A chronotype is the time of day when a person naturally feels most energetic; it has a strong genetic basis, though environmental factors also shape it.
How the study was done
Scientists tracked 5,679 adults born in two regions of Northern Finland over 12 years. In 2012, when participants were 46, they answered questions about morning tiredness, preferred working hours and whether they considered themselves morning or evening people. The analysis included 2,597 men and 3,082 women who had not yet retired and were not receiving a disability pension.
About 10% of the men and 12% of the women were classed as evening types. Of these, 70% worked a standard schedule, with the workday starting at 8:00 a.m.
Results
In Finland, a disability pension is granted when health problems substantially reduce long-term capacity to work. During the follow-up, 384 participants received one. Among men, work incapacity was recorded in 8.3% of owls and 5% of larks. Among women, the figures were 12.1% and 7.2%. Overall, the rate of pension awards among evening types was about 70% higher. The link appeared in both men and women and held after accounting for education and income.
Possible reasons
Lead author Tapio Reihe, a health researcher at the University of Oulu, told ScienceAlert that the most likely explanation is that evening types generally have poorer health. A key factor is insufficient sleep, because the body's internal clock does not match standard working hours.
Recommendations
The authors suggest going to bed on time, switching off screens a few hours beforehand and dimming the lights. Another option is arranging one's routine so that it is possible to sleep in. Reihe added that a job with flexible hours could also help.
