Johan Björkqvist1, Juulia Paavonen2, Sture Andersson3, Anu-Katriina Pesonen4, Jari Lahti4, Kati Heinonen4, Johan Eriksson5, Katri Räikkönen4, Petteri Hovi6, Eero Kajantie6, Sonja Strang-Karlsson6. 1. Children's Hospital, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland; National Institute for Health and Welfare, Helsinki, Finland. Electronic address: johan.bjorkqvist@helsinki.fi. 2. Child Psychiatry, Helsinki and Uusimaa Hospital District, Helsinki, Finland; National Institute for Health and Welfare, Helsinki, Finland. 3. Children's Hospital, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland. 4. Institute of Behavioural Sciences, University of Helsinki, Helsinki, Finland. 5. National Institute for Health and Welfare, Helsinki, Finland; Department of General Practice and Primary Health Care, University of Helsinki, Helsinki, Finland; Vasa Central Hospital, Vasa, Finland; Unit of General Practice, Helsinki, Finland; Folkhälsan Research Centre, Helsinki, Finland. 6. Children's Hospital, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland; National Institute for Health and Welfare, Helsinki, Finland.
Abstract
OBJECTIVE: Previous studies have suggested a propensity towards morningness in teenagers and adults born preterm. We set out to study sleep in a subsample from The Helsinki Study of Very Low Birth Weight Adults cohort, with emphasis on sleep timing, duration, and quality. We compared young adults who were born prematurely at very low birth weight (VLBW; <1500 g) with controls born at term. METHODS: We measured sleep by actigraphy in young adults aged 21-29 years. A total of 75 individuals (40 VLBW and 35 controls) provided adequate data. Group differences in sleep parameters were analyzed using t-test and linear regression models. RESULTS: VLBW adults woke up on average 40 min earlier [95% confidence interval (CI), 9-70] and reported 40 min earlier get up time (95% CI, 8-71) than did the controls. The difference remained after adjustment for confounders. We found no group difference in sleep duration or measures of sleep quality. CONCLUSION: Our findings of earlier rising in the VLBW group are suggestive of an advanced sleep phase in that group. These results reinforce previous suggestions that chronotype may be programmed early during life.
OBJECTIVE: Previous studies have suggested a propensity towards morningness in teenagers and adults born preterm. We set out to study sleep in a subsample from The Helsinki Study of Very Low Birth Weight Adults cohort, with emphasis on sleep timing, duration, and quality. We compared young adults who were born prematurely at very low birth weight (VLBW; <1500 g) with controls born at term. METHODS: We measured sleep by actigraphy in young adults aged 21-29 years. A total of 75 individuals (40 VLBW and 35 controls) provided adequate data. Group differences in sleep parameters were analyzed using t-test and linear regression models. RESULTS: VLBW adults woke up on average 40 min earlier [95% confidence interval (CI), 9-70] and reported 40 min earlier get up time (95% CI, 8-71) than did the controls. The difference remained after adjustment for confounders. We found no group difference in sleep duration or measures of sleep quality. CONCLUSION: Our findings of earlier rising in the VLBW group are suggestive of an advanced sleep phase in that group. These results reinforce previous suggestions that chronotype may be programmed early during life.