[Characteristics of male shift workers' drinking habits and factors related to drinking problems].

Objectives　To clarify the characteristics of shift workers' drinking habits, as well as factors related to their drinking problems, and obtain an insight into the early detection of such problems and appropriate interventions.Methods　An anonymous self-completed questionnaire survey was conducted involving all employees of a factory. All the shift workers were male. Considering the sex differences, we excluded daytime female workers from the study. The number of participants was 230. The questionnaire inquired the presence or absence of drinking problems, drinking habits, and factors related to these problems. We analyzed the relationship between shift work and drinking problems, shift work and each drinking habit, and drinking problems and each drinking habit. Binomial logistic regression analysis using the backward elimination method was conducted, with "the presence/absence of alcohol related problems" as the dependent variable, and variables showing the value of P<0.20 through univariate analysis as independent variables, with age, inputted simultaneously.Results　The drinking habits of shift workers compared to daytime workers were characterized by a significantly higher percentage of those drinking "at home" (P=0.037). In addition, compared with daytime workers, shift workers showed a significantly higher percentage of those reporting a "desire to sleep well" as the reason for drinking (P=0.006), and a significantly higher percentage of those having a nightcap (P<0.001). Significant correlations were seen between increased risk of drinking problems and "having a nightcap" (OR 6.38, 95%CI: 2.11-19.29, P=0.001) as well as "having a heavy physical job stress burden" (OR 2.24, 95%CI: 1.11-4.51, P=0.024). On the other hand, "receiving support from family and friends" had a significant correlation with a reduced risk of drinking problems (OR 0.75, 95%CI:0.58-0.97, P=0.030).Conclusions　Characteristics of male shift workers' drinking habits and factors related to drinking problems indicated that the drinking habits of shift workers compared to daytime workers were characterized by a significantly higher percentage of those drinking "at home" and "having a nightcap". "Having a nightcap" and "having a heavy physical burden" were correlated with an increased risk of drinking problems in male shift workers, whereas "support from family and friends" was correlated with a reduced risk of drinking problems. It is considered important to understand difficulties in falling asleep after working the night shift and to support coping behaviors other than drinking. Furthermore, elucidation of the importance of support from friends and family is necessary.