Short sleep duration and smoking initiation in university students: a retrospective cohort study.

PURPOSE: The aim of this study was to clarify an association between short sleep duration and smoking initiation. METHODS: Participants eligible for this retrospective cohort study were university students who were admitted to a single national university in Japan between 2007 and 2015. Baseline sleep duration and smoking status were measured using general questionnaires at health checkups at admission. During a 6-year observation period, smoking initiation was assessed using general questionnaires at annual health checkups. Cox proportional hazards models adjusted for clinically relevant factors were used to assess the association between sleep duration and smoking initiation. RESULTS: Of 17,493 men, including 540, 5,568, 8,458, 2,507, and 420 men with sleep duration of < 5, 5-6, 6-7, 7-8, and ≥ 8 h, respectively, smoking initiation was observed in 16.1%, 12.5%, 11.2%, 10.0%, and 11.7%, respectively, during a median observation period of 3.0 years. Men with shorter sleep duration were at a higher risk of smoking initiation (adjusted hazard ratio 1.49 [95% confidence interval 1.19-1.85], 1.11 [1.01-1.22], 1.00 [reference], 0.92 [0.80-1.06], and 1.00 [0.75-1.34], respectively). Of 8,880 women, including 267, 3,163, 4,220, and 1,230 women with sleep duration of < 5, 5-6, 6-7, and ≥ 7 h, respectively, smoking initiation was observed in 4.9%, 2.3%, 2.0%, and 2.2%, respectively, during a median observation period of 3.0 years. A similar dose dependent association was ascertained in women (2.50 [1.39-4.49], 1.18 [0.86-1.62], 1.00 [reference], and 1.22 [0.79-1.89], respectively). CONCLUSION: This study clarified that university students with short sleep duration were vulnerable to smoking initiation.

Living Arrangements Predict Frequent Alcohol Consumption Among University Students: A Retrospective Cohort Study.

PURPOSE: This study aimed to confirm the clinical impact of living arrangements on incidence of frequent alcohol consumption in university students. DESIGN: A retrospective cohort study. SETTING: A national university in Japan. SUBJECTS: 17,774 university students. MEASURES: The association between living arrangements on admission and the incidence of frequent alcohol consumption (≥4 days/week) was assessed using multivariable-adjusted Cox proportional-hazards models. RESULTS: Among 5,685, 692, and 5,151 male students living with family, living in the dormitory, and living alone, 5.0%, 6.2%, and 5.8% reported frequent alcohol consumption during the median observational period of 3.0 years, respectively. Living in the dormitory and living alone were identified as significant predictors of frequent alcohol consumption (multivariable-adjusted hazard ratios: 1.00 [reference], 1.39 [1.01-1.92], and 1.21 [1.03-1.42], respectively). On the contrary, living arrangements were not associated with the incidence of frequent alcohol consumption among of 6,091 female students, partly because of low incidence of frequent alcohol consumption (2.3%, 1.4%, and 2.6%, respectively). CONCLUSIONS: Living arrangements predicted frequent alcohol consumption among male university students, whereas not among female university students.

Skipping Breakfast and Incidence of Frequent Alcohol Drinking in University Students in Japan: A Retrospective Cohort Study.

Frequency of alcohol drinking is a potential predictor of binge drinking of alcohol, a serious social problem for university students. Although previous studies have identified skipping breakfast as a predictor of various health-compromising behaviors and cardiometabolic diseases, few studies have assessed the association between skipping breakfast and the incidence of frequent alcohol drinking. This retrospective cohort study included 17,380 male and 8799 female university students aged 18-22 years admitted to Osaka universities between 2004 and 2015. The association between breakfast frequency (eating every day, skipping occasionally, and skipping often/usually) and the incidence of frequent alcohol drinking, defined as drinking ≥4 days/week, was assessed using multivariable-adjusted Cox proportional hazards models. During the median observational period of 3.0 years, 878 (5.1%) men and 190 (2.2%) women engaged in frequent alcohol drinking. Skipping breakfast was significantly associated with the incidence of frequent alcohol drinking (adjusted hazard ratios [95% confidence interval] of eating every day, skipping occasionally, and skipping often/usually: 1.00 [reference], 1.02 [0.84-1.25], and 1.48 [1.17-1.88] in men; 1.00 [reference], 1.60 [1.03-2.49], and 3.14 [1.88-5.24] in women, respectively). University students who skipped breakfast were at a higher risk of frequent alcohol drinking than those who ate breakfast every day.