RESUMEN
BACKGROUND: The degree to which the relationship between alcohol use and sleeplessness is unidirectional or reciprocal is unclear due to great variation among the results of previous studies. The aim of the present study was to investigate if the relationship between alcohol use and sleeplessness is bidirectional by exploring how the change in and stability of alcohol use were related to sleeplessness, and vice versa, how the change in and stability of sleeplessness were related to alcohol use, in a longitudinal study spanning 13 years. METHOD: Data were collected from 9941 adults who participated in two waves (T1: 1994-1995, and T2: 2007-2008) of the Tromsø Study, a Norwegian general population health study. Alcohol use was measured by questions asking about the frequency of drinking, amounts of alcohol normally consumed and the frequency of binge drinking, whereas sleeplessness was measured by one item asking about the frequency of experiencing sleeplessness. Variables representing change in and stability of consumption of alcohol and sleeplessness from T1 to T2 were created. Logistic regression analyses, stratified by gender, were used to analyze the data. RESULTS: Men reporting stable high (OR = 2.11, p. < .001) or increasing (OR = 1.94, p. < .01) consumption of alcohol from T1 to T2 had a significantly higher risk of reporting sleeplessness at T2. Likewise, men experiencing stable (OR = 1.84, p. < .01) or increasing (OR = 1.78, p. < .001) sleeplessness from T1 to T2 had a significantly higher risk of reporting high consumption of alcohol at T2. No significant effects were detected among women. CONCLUSION: The findings indicate a bidirectional relationship between high consumption of alcohol and sleeplessness only among men. Thus, healthcare professionals ought to be informed about the health risks associated with excessive drinking and struggling with sleeplessness, especially in men.