A new study has found that working night shifts is linked to a higher risk of osteoporosis and related fractures. The research, published in Frontiers in Public Health, analyzed data from more than 270,000 adults in the UK. It compared those who worked regular daytime hours with people who worked night shifts or had previous exposure to night work.
Osteoporosis is a condition where bones become weak and are more likely to break. Many people do not know they have it until a fracture occurs. Risk factors include aging, hormonal changes such as menopause, genetics, low body mass index, certain medications, smoking, heavy alcohol use, and lack of physical activity.
According to the National Center for Health Statistics (NCHS), over half of Americans aged 50 and older either have osteoporosis or are at increased risk due to low bone mass. The American Academy of Orthopedic Surgeons (AAOS) notes that prevention strategies like exercise and lifestyle changes can help reduce this risk.
The study used information from the UK Biobank, which includes health data on more than 500,000 people aged 40 to 69. Researchers excluded anyone already diagnosed with osteoporosis. Participants reported their work schedules and were grouped based on how often they worked nights: never or rarely, some nights, or usual/permanent night shifts.
Results showed that those who regularly worked night shifts had the highest risk of developing osteoporosis. Even those with some history of night shift work faced an increased risk compared to day workers. Longer duration and greater frequency of night shift work were generally linked with higher odds of osteoporosis.
Night shift workers tended to be younger men with less education and lower socioeconomic status. They also reported shorter sleep times and later sleep patterns.
The researchers adjusted for various factors such as age, sex, body mass index (BMI), chronic diseases, cancer history, sleep habits, outdoor time, supplement use, and female-specific variables. These adjustments did not change the overall findings.
Genetic analysis showed that individuals with a higher genetic predisposition also had a greater risk for osteoporosis but there was no significant interaction between genetics and night shift work regarding this risk.
"Although the relative risk was elevated, the absolute risk of osteoporosis for any individual worker remained low," the authors wrote. "These results suggest that occupational health policies could consider incorporating regular bone density monitoring and lifestyle modifications to help mitigate osteoporosis risk in this vulnerable population."
The study concludes that while working night shifts does not cause osteoporosis directly, it is associated with an increased likelihood of developing it over time. The findings highlight the importance of targeted screening and preventive measures for workers exposed to long-term or frequent night shifts.
