SLEEPING PROBLEMS AT 78 DEGREES NORTH - THE SVALBARD STUDY

The aim of this study was to compare the prevalence of sleeping proble ms in two ethnically different populations living under the same extre me arctic climate. A total of 453 Norwegians (319 males and 134 female s) were compared with 450 Russians (317 males and 133 females), all ag ed 18 years or older, living on Svalbard, the northernmost regular set tlement in the world. Among Russians, 81% of the male subjects and 77% of the female subjects reported sleeping problems lasting for at leas t 2 weeks. The corresponding figures for the Norwegians were 22% (for males) and 25% (for females). Among Russians, sleeping problems decrea sed with increasing age, but no such age trend was found in Norwegians . Whereas sleeping problems among Norwegians were approximately equall y frequent throughout the year, the Russians reported more problems du ring the polar night. 'Problems falling asleep', 'not feeling rested i n the morning' and 'waking up several times during the night' were the most frequent types of sleeping problems in both groups. Depression, shift work, loneliness, ability to concentrate, alcohol consumption an d quality of Life were associated with sleeping problems in Norwegian subjects, whereas depression, shift work, ability to concentrate, and worry were associated with sleeping problems in Russians. The prevalen ce of sleeping problems was nearly fourfold higher among Russian subje cts than among Norwegians living on Svalbard. As the Russians were rec ruited from a lower latitude than the Norwegians, we postulate that th eir problems should be interpreted in terms of inadequate acclimatizat ion after migration to the north.