# Association between night shift work and risk of osteoporosis and osteoporosis-related pathological fracture

## TL;DR

Working night shifts is linked to a higher risk of osteoporosis and related fractures, even after accounting for genetic and lifestyle factors.

## Contribution

This study identifies a significant association between night shift work and increased osteoporosis risk, independent of genetic susceptibility.

## Key findings

- Night shift workers showed a 29% higher risk of osteoporosis compared to day workers.
- Long-term night shift work was associated with a 38% increased risk of osteoporosis.
- Night shift work was linked to an 88% higher risk of osteoporosis-related fractures.

## Abstract

Night shift work may increase the risk of various diseases, this study aims to explore the associations of both past and current night shift rotations with osteoporosis and its related fracture risks, and to evaluate the role of potential mediators further in the UK biobank.

We investigated 276,774 UK Biobank participants with current paid employment or self-employed work, alongside 75,120 individuals with lifetime occupational history information. The multivariable-adjusted logistic regression and Cox proportional hazard models were utilized to analyze the potential links between night shift work and the incidence of OP. Moreover, stratified analyses and interaction tests were applied to explore potential modifications.

A total of 276,774 participants aged 40 to 69 years (mean ± SD: 52.7 ± 7.1); among them, 143,081 women (51.7%); 260,994 White participants (94.3%) were included, and a total of 5,906 OP events were documented. Relative to “day workers,” all subgroups engaged in night shifts displayed a notable increase in OP prevalence (P for trend < 0.001). The usual night shifts with the highest risk [hazard ratio (HR) 1.29, 95% confidence interval (CI) 1.12–1.50]. Besides, the results of lifetime night shift schedules showed the highest OP risk participants with duration >10 years [OR 1.21, 95% CI (0.92–1.58)] and 3–8 shifts/month [OR 1.38, 95% CI (1.11–1.72)] exposure. In addition, these positive associations remained unaltered by sensitivity and stratified analyses with various confounders and genetic vulnerability (all P for interaction > 0.05). Furthermore, we observed a positive association between night shifts and OP-related pathological fractures [HR 1.88, 95% CI (1.20–3.94)].

This study demonstrated that both current and lifetime night shifts was significant associated with the greater risk of OP and its related pathological fracture. Additionally, these associations were not modified by genetic susceptibility. The potential of reducing night shift work as a strategy for preventing osteoporosis requires further investigation.