1. Sleep Research Unit (N.K., P.P.-K., A.V., O.P.), University of Turku, FIN-20520, Turku, Finland
2. Department of Obstetrics and Gynecology (P.P-K.), Turku University Central Hospital, FIN-20520, Turku, Finland
3. Department of Mehiläinen Oy (K.I.), FIN-20520 Turku, Finland
4. Department of Physiology (T.P.-H.), University of Helsinki, FIN-00014 Helsinki, Finland
5. Department of Physiology, and Departments of Biostatistics (T.V.), University of Turku, FIN-20520, Turku, Finland
6. Department of Mathematics (A.V.), University of Turku, FIN-20520, Turku, Finland
7. Department of Pulmonary Diseases (O.P.), Tampere University Hospital, FIN-33521 Tampere, Finland