[Study of chronic pain and its associated risk factors among Japanese industry workers: the Quality of Working Life Influenced by Chronic pain (QWLIC) study]

Association between smoking and central sensitization pain: a web-based cross-sectional study

PURPOSE

This study aimed to investigate whether smoking is an independent risk factor for central sensitization syndrome (CSS) in individuals with pain as measured by the Central Sensitization Inventory (CSI).

METHODS

In 2020, we conducted an Internet survey targeting 2000 ordinary residents of Japan (aged 20-69 years) who had pain symptoms from October to November 2020. A multiple regression analysis was performed on the association between smoking status (nonsmokers and current smokers; Brinkman index) and CSI values. Moreover, compared to nonsmokers, the relative risk (RR) of the CSI cut-off score of 40 points or higher among current smokers was calculated using a modified Poisson regression model. Covariates included age, sex, body mass index, marital status, equivalized income, exercise habits, history of hypertension, history of hyperlipidemia, history of diabetes, pain chronicity, and Pain Catastrophizing Scale score.

RESULTS

This study analyzed 1,822 individuals (1,041 men and 781 women). Among those experiencing pain, current smoking was associated with the increase in CSI values (β = 0.07). The Brinkman index was also significantly associated with the increase in CSI values (β = 0.06). Current smoking also increased the risk of being over the CSI cut-off score, with a relative risk (RR) of 1.29 (95% confidence intervals, 1.04-1.60). Younger age, being women, experiencing chronic pain, and higher pain catastrophizing thinking were also significantly associated with increased CSS severity, independent of smoking status.

CONCLUSION

Smoking is an independent risk factor for CSS. This indicates that smoking may be an important factor in the management of central pain disorders.

Cross-Sectional Study of Prevalence, Characterization and Impact of Chronic Pain Disorders in Workers

Chronic pain prevention and treatment constitute a challenge for occupational health The aim of this study was to provide data on workers in a variety of jobs and multiple contexts to determine the prevalence and characteristics of different chronic pain disorders, in view to highlighting possible new targets for preventive actions. 1,008 participants working in 14 French IKEA stores were analyzed in this observational study on the basis of their responses to surveys on their sociodemographic characteristics, psychosocial factors, lifestyle, and pain disorders. The prevalence of chronic pain, moderate-to-severe chronic pain and high-impact chronic pain were 49%, 30%, and 11%, respectively. Chronic pain was predominantly located in the neck and back, and identified mostly as nociceptive, with, for some participants, a neuropathic component (mixed pain). The majority of chronic pain was reported as being due to professional activity, and causing at least one work stoppage during the past year in half of the participants. Jobs that were the most common sources of chronic pain were those with a higher proportion of repetitive gestures, no consecutive days of rest, stress at work, such as cash-register/catering jobs. Overall, this study highlighted profiles at risk of developing or suffering from chronic pain, and several associated factors: ≥40 years old, female sex, overweight/obesity, repetitive gestures, no consecutive days of rest, stress, catastrophism, workplace environment, poor quality of life, and mental state. In conclusion, these data give interesting information on the characteristics of workers with chronic pain and highlight profiles of participants. Perspective: This study provides important information about the features of chronic pain in a model of a working population of Western countries. This information can be used to propose preventive actions.

Smoking is associated with greater pain intensity and pain-related occupational disability in Japanese workers

PURPOSE

Pain symptom, such as that caused by musculoskeletal disorders, is a major cause of occupational disability. As nicotine intake from smoking increases pain sensitivity, smokers may experience stronger pain and be more likely to experience pain-related disability than non-smokers. The study aim was to examine whether smoking was associated with pain-related occupational disability via pain intensity.

METHODS

Participants were 1189 workers with pain aged 20-74 years in Japan. Participants completed a self-report questionnaire, which included a question to measure pain-related occupational disability with ordinal-option: (1) without pain-related disability, (2) pain-related presenteeism, and (3) pain-related absenteeism. An ordinal logistic regression model was used to calculate multivariable-adjusted proportional odds ratios (OR) with 95% confidence intervals (CI) for the prevalence of pain-related occupational disability according to smoking status. A multiple mediation analysis was also conducted to assess whether pain sensitivity mediated the association between smoking and pain-related occupational disability. Adjusted variables were demographic variables, socioeconomic status, work-related psychosocial factors, general psychological factors, and pain duration.

RESULTS

Current smoking and pain were associated with pain-related occupational disability compared with non-smoking and pain (multivariable OR 1.78; 95% CI 1.26-2.52). Greater pain intensity partially mediated the association of current smoking and pain with pain-related occupational disability. The mediation rate (indirect/total effect) was 25%.

CONCLUSION

Smoking and pain were associated with pain-related occupational disability, partially through greater pain intensity, among Japanese workers.

Relationships Between Chronic Musculoskeletal Pain and Working Hours and Sleeping Hours: A Cross-sectional Study

Ten to twenty percent of the population of Japan has chronic pain. Although studies have confirmed a relationship between sleeping hours and chronic pain, it remains unclear whether there is an association between working hours and chronic pain, especially chronic musculoskeletal pain (CMP), in workers. A self-administered questionnaire that sought information regarding background characteristics and work-related factors was sent to 118 enterprises; finally, 1,747 participants were included in the analysis and were classified into CMP (n = 448) and non-CMP (n = 1299) groups. Logistic regression analysis revealed that age (odds ratio [OR] = 1.02, 95% confidence interval [CI]: 1.01-1.03), sex (reference: female, OR = 0.68, 95% CI: 0.52-0.88), working hours (OR = 1.11, 95% CI: 1.03-1.20), and sleeping hours (OR = 0.84, 95% CI: 0.75-0.95) were significantly associated with CMP. Participants were categorized into four groups according to working hours (long: ≥ 9 hours/day [long-work], short: < 9 hours/day [short-work]) and sleeping hours (long: ≥ 7 hours/day [long-sleep], short: < 7 hours/day [short-sleep]). Furthermore, logistic regression analysis showed that the CMP OR was 2.02 (95% CI: 1.46-2.78) times higher in 'long-work plus short-sleep workers' and 1.47 (95% CI: 0.94-2.30) times higher in 'long-work plus long-sleep workers' than in 'short-work plus long-sleep workers'. Thus, working hours are associated with CMP frequency, but sleeping sufficiently may prevent CMP in workers even if they work for long hours. In conclusion, adequate instructions on sleeping hours should be provided by occupational health staff, as this may be effective in preventing CMP.