Persistent BMI and height deficits reflect structural and geographic inequities among adolescent girls in Nepal.

Adolescence is a period of rapid growth; however, many adolescent girls experience suboptimal growth trajectories. This longitudinal study assessed changes in body mass index (BMI) and linear growth and associated factors among Nepali adolescent girls from 2017-2019. We analysed panel data from three waves (2017 [n=770], 2018 [n=682] and 2019 [n=618]) of never-married and non-pregnant girls aged 10-19 years in 2017. BMI-for-age difference (BMI-AD) and height-for-age difference (HAD), indicating deviation from WHO age- and sex-specific medians, were used to assess change over time. BMI-AD and conditional growth (calculated as residuals from regressions of 2018/2019 HAD on prior HAD and age) were used in the regression analyses to identify associated factors. Conditional growth reflects linear growth above or below what would be expected, based on prior height and age. We used descriptive statistics to assess change, and linear mixed-effects and ordinary least squares regression to identify factors associated with BMI-AD and conditional growth, respectively. Findings confirmed that girls consistently had lower BMI (-1.78kg/m2, -1.60kg/m2 and -1.48kg/m2 respectively in 2017, 2018, 2019) and height relative to the WHO median for their age and sex (-10.3cm, -10.2cm and -9.9cm respectively in 2017, 2018, 2019), with negligible improvements. Factors associated with higher BMI-AD were post-menarche status (0.98kg/m2, 95% CI 0.72, 1.25), higher education (0.11kg/m2, 95% CI 0.01, 0.21), and disadvantaged caste/ethnicity (0.48kg/m2, 95% CI 0.14, 0.83); in contrast, older age (-0.17kg/m2, 95% CI -0.27, -0.07), food insecurity (-0.31kg/m2, 95% CI -0.57, -0.06), and terai (-0.93kg/m2, 95% CI -1.45, -0.40) or hill (-0.57kg/m2, 95% CI -1.06, -0.08) residence were associated with lower BMI-AD. For conditional linear growth, older age (0.19cm, 95% CI 0.14, 0.24 for 2018; 0.16cm, 95% CI 0.11, 0.21 for 2019) and underweight (0.25cm, 95% CI 0.10, 0.40 for 2018) predicted higher gains than expected given their prior height and age, whereas post-menarche status (-0.94cm, 95% CI -1.16, -0.72 for 2018; -1.03cm, 95% CI -1.25, -0.82 for 2019) and terai (-0.35cm, 95% CI -0.62, -0.08 for 2018; -0.31cm, 95% CI -0.59, -0.03 for 2019) hill (-0.25cm, 95% CI -0.48, -0.02 for 2019) residence predicted lower growth than expected given their prior height and age. Findings highlight the need to address age-related nutrition, education, food insecurity, and geographic disparities to support healthy growth.