Occupational status and self-reported low back pain by gender: a nation-wide cross-sectional study among the general population in Japan

Abstract

Background

We aimed to examine the cross-sectional association between occupational class and self-reported low back pain (LBP) in a representative sample of the Japanese general population.

Methods

We used anonymized data from a nationwide survey (31,443 men and 35,870 women aged ≥ 20). Occupational class variables included working status, occupation, employment status, and company size (number of employees). Covariates included age, socio-economic status, lifestyle, and comorbidities. Poisson regression models stratified by gender were used to estimate adjusted prevalence ratio (APR) and 95% confidence interval (CI) for self-reported LBP.

Results

The prevalence of self-reported LBP was 11.7% in men and 14.2% in women. After adjustment for covariates and mutual adjustment for all occupational class variables, among both genders, agricultural/forestry/fishery workers and non-workers had a significantly higher prevalence of self-reported LBP: APR (95% CI) of agricultural/forestry/fishery was 1.36 (1.08–1.70) in men and 1.59 (1.30–1.93) in women; that of non-workers was 1.42 (1.18–1.70) in men and 1.23 (1.08–1.40) in women. Among men, non-regular employees were more likely to have self-reported LBP than regular employees: APR (95% CI) was 1.25 (1.07–1.46) in part-timers and casual staff and 1.18 (1.03–1.35) in other types of non-regular employees. Moreover, compared to men working at companies with ≥ 100 employees, men working at companies with 30–99 employees had a significantly higher prevalence of self-reported LBP (APR 1.17; 95% CI, 1.03–1.34). Among women, professionals and technicians (1.26; 1.11–1.43) and sales workers (1.22; 1.04–1.43) had a significantly higher prevalence of self-reported LBP than clerks. Neither employment status nor company size was associated with self-reported LBP in women. After stratified analyses by age group, similar patterns were observed in participants aged 20–64, but not in those aged ≥ 65.

Conclusion

Our results suggest that self-reported LBP is highly prevalent among agricultural/forestry/fishery workers and the unemployed, regardless of gender, and that there are also gender differences in the association of occupational class factors with self-reported LBP. It is necessary, therefore, to take preventive measures against LBP based on gender and occupational class factors in Japan.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12199-021-01031-2.