Plain-language · Issue 1 · 2026-09-29
Gestational Age Weakly Predicts Physical Activity Levels in Adolescents and Adults: A Registry Linkage Study from Norway
Editorially reviewed research summaries, context, and limitations.
Kristina Anna Djupvik Aakvik, Silje Dahl Benum, Marjaana Tikanmäki, et al.
Summary: Norwegian researchers linked physical activity measurements from 12,896 participants in the HUNT Study — a large, long-running population health study — with birth records from Norway's national birth registry. Participants wore motion-tracking devices to measure how active they actually were (rather than relying on self-report). The analysis found that being born earlier than expected — at a shorter gestational age — was modestly associated with lower physical activity levels, particularly for light activity in females and total activity in adolescents. Birth weight, on its own, showed no association with how active people were later in life.
Why it matters: Whether the circumstances of birth have lasting effects on health behaviors like physical activity is an important public health question, because activity levels influence the risk of many chronic diseases across a lifetime. The methods used here — connecting a high-quality population study to a national birth registry — offer a useful model for life-course research that other registry systems could replicate. For anyone interested in how registry data can be linked across time and data sources, this study is a practical illustration of what is possible with well-maintained national records.
What to keep in mind: The associations found were statistically detectable but very small in practical terms — the difference in activity linked to being born a week earlier or later was minimal across most of the population studied. The study combined people aged 13 to 52 into a single analysis, a very wide range that spans very different life stages, and patterns in birth and obstetric care changed substantially over the decades when these participants were born. Very premature births — the group most studied in other research — were likely underrepresented here, since many very premature babies born in earlier decades did not survive to adulthood. The analysis adjusted for age and sex but not for many other factors — such as a mother's health, family income, or social circumstances — that could both affect the timing of birth and shape how active someone becomes later in life. These unmeasured factors mean the study cannot establish that gestational age itself caused the differences in activity. The primary scientific contribution is the demonstration of how registry linkage can be done, rather than a definitive finding about birth and physical activity.
Relevance: Registry and Real-World Data Methods