Alcohol and smoking increase the risk of premature death among midnighters, but not nightlife per se, say scientists from the Finnish Institute of Occupational Health in Helsinki. Their study, which began in 1981 and continued through 2018, involved nearly 23,000 twins, men and women.
At the beginning of the data collection, participants were asked to choose one of four possible answers to the question about chronotype: “I am clearly a morning person,” “I am somewhat of a morning person,” “I am clearly an evening person,” “I am somewhat of an evening person.” By 2018, nearly nine thousand participants had died, and people with a distinctly evening chronotype were 9% more likely to die from any cause than people with a morning chronotype.
However, the study found that smoking and alcohol, rather than the chronotype itself, were largely responsible for these deaths. Non-smokers of the midnight chronotype had no increased risk of death. The study authors took into account education, daily alcohol consumption, number of cigarettes smoked, BMI, and sleep duration.
Causes of death from alcohol included comorbidities as well as accidental alcohol poisoning. Compared to larks, night owls were younger and drank and smoked more. The results of the study showed that about eight thousand twins identified themselves as “somewhat evening people,” and two thousand identified themselves as “clearly evening people.” The number of hesitant and overtly morning people was six and seven thousand, respectively.
There is growing evidence that the length and quality of sleep, as well as working the night shift, affect health. Earlier studies linked nighttime lifestyles to a higher risk of disease, especially heart problems. The new study compares favorably with previous studies because the authors analyzed the lifestyles of the participants.
Interestingly, other studies have also previously shown a link between nightlife and health. For example, in 2018, the journal JAMA Psychiatry published a study in which researchers from the University of Southampton found that people who work night shifts have a higher risk of developing depression and anxiety disorders.
But a new study from Finland emphasizes that it is not the nightlife itself that causes premature death, but smoking and alcohol. So it’s important to remember the dangers of these bad habits and try to avoid them, especially if you’re a midnight drinker.
“This study confirms that smoking and alcohol are two important health risk factors that can increase the likelihood of premature death in people with a certain chronotype. However, this does not mean that the nighttime lifestyle is safe. Night shift work, lack of sleep and other factors can also have a negative impact on health,” says Professor Richard Stevens of the University of Southampton.