The purpose of this work was to examine the relationships between geographical coordinates and the prevalence of @entity308 (SADW ), and to compare the sleep characteristics and chronotype of youths with and without SADW . We conducted a cross-sectional study of self-reported sleep characteristics, chronotype and @entity308 in northern European Russia. Two questionnaires, the Munich Chronotype Questionnaire (MCTQ) and the Seasonal Pattern Assessment Questionnaire (SPAQ), were administered to a total of 3435 adolescents aged 10-20  years (1517 males and 1918 females). The prevalence of SADW in the study population was 8.4% and sub-SADW 11.8%. Four variables predicted the likelihood of SADW in youths: sex [higher in females: odds ratio (OR): 1.87, P  <  0.0001], age (increases with age: OR: 1.09, P  <  0.001), latitude (higher in the North: OR: 1.49, P  <  0.029) and position in the time zone (higher in the West: OR: 1.61, P  <  0.001). Later sleeping and waking, longer sleep latencies, more severe @entity25 , @entity25 and @entity25 were observed in both males and females with SADW . The influence of SADW on sleep characteristics was more pronounced on school days. Significant phase delays of the sleep-wake rhythm and severe social jetlag (the difference between the mid-point of sleep phase at weekends and on workdays) were observed in females with SADW , but not in males. There are significant differences in sleep characteristics and chronotype between @entity1 with SADW and no- @entity4696 . We demonstrate that both latitude of residence and location within the time zone are significant predictors of SADW in young inhabitants of the North.

Sleep characteristics, chronotype and XXXX in 10-20-year-olds in northern European Russia.

@entity1 :: ('9606', 'Species') :: ['people'] @entity4696 :: ('MESH:D003865', 'Disease') :: ['SAD'] @entity308 :: ('MESH:D003866', 'Disease') :: ['winter depression'] @entity25 :: ('MESH:D012893', 'Disease') :: ['shorter total sleep times', 'lower sleep efficiencies', 'sleep inertia']
@entity308 :: (MESH:D003866,Disease) :: ['winter depression']
