2134/36608 Sarah Crozier Sarah Crozier Will Johnson Will Johnson Tim J. Cole Tim J. Cole Corrie Macdonald-Wallis Corrie Macdonald-Wallis Graciela Muniz-Terrera Graciela Muniz-Terrera Hazel Inskip Hazel Inskip Kate Tilling Kate Tilling A discussion of statistical methods to characterize early growth and its impact on bone mineral content later in childhood Loughborough University 2019 Growth mixture models Lifecourse epidemiology Linear spline models Multilevel models SITAR Medical and Health Sciences not elsewhere classified 2019-01-17 10:57:10 Journal contribution https://repository.lboro.ac.uk/articles/journal_contribution/A_discussion_of_statistical_methods_to_characterize_early_growth_and_its_impact_on_bone_mineral_content_later_in_childhood/9626477 Background Many statistical methods are available to model longitudinal growth data and relate derived summary measures to later outcomes. Aim To apply and compare commonly used methods to a realistic scenario including pre- and postnatal data, missing data and confounders. Subjects and methods Data were collected from 753 offspring in the Southampton Women’s Survey with measurements of bone mineral content (BMC) at age 6 years. Ultrasound measures included crown-rump length (11 weeks’ gestation) and femur length (19 and 34 weeks’ gestation); postnatally, infant length (birth, 6 and 12 months) and height (2 and 3 years) were measured. A residual growth model, two-stage multilevel linear spline model, joint multilevel linear spline model, SITAR and a growth mixture model were used to relate growth to 6-year BMC. Results Results from the residual growth, two-stage and joint multilevel linear spline models were most comparable: an increase in length at all ages was positively associated with BMC, the strongest association being with later growth. Both SITAR and the growth mixture model demonstrated that length was positively associated with BMC. Conclusions Similarities and differences in results from a variety of analytic strategies need to be understood in the context of each statistical methodology.