4. Discussion
HIV and chronic lung disease, might gain, CLD, comorbidity
OBESE, CARDIOVASCULAR DISEASE, SECONDARY, TYPE 2 DIABETES, CLD
This secondary data analysis of cohort and RCT data characterised seven growth profiles among children and adolescents from Southern Africa and included individuals living with HIV, with both HIV and chronic lung disease, as well as HIV-negative children. The majority of individuals exhibiting average growth (profile 1), defined as Z-scores around 0.5 SD below the UK population reference, were HIV-negative school children. Two profiles differentiated individuals who had BMI-for-age Z-scores around 1 SD above the UK reference, with their weight relatively high for their height, into those who were tall for their age (profile 2, more likely to be older HIV-negative children) and those who were short for their age (profile 3, more likely to be older CWH). Although few of these individuals were classified as obese, the highest percentage total body fat coincided with these profiles which were dominated by females. The second most common profile was stunted not thin (profile 4), which were a group of children, the majority CWH, whose body size was proportionate to their shorter height. Some of these individuals were younger than those in profiles 2 and 3, so they might gain further height as they progress through puberty, but have started puberty with a legacy of early growth faltering. Profile 5, thin not stunted, was more common among 11–14 year-olds and could indicate a recent growth spurt and pubertal transition. Profile 6, thin and stunted and profile 7: very thin and stunted were more common among CWH, males and at older age, and indicate growth faltering; profile 6 was the largest profile among CWH with CLD (BREATHE RCT). profile 7 was the rarest profile, with the lowest Z-scores but the vast majority in this profile were CWH with co-morbid CLD from the BREATHE RCT.HIV was associated with growth profiles demonstrating poor linear growth (profiles 3–7) supporting other studies which have shown growth faltering in early childhood among CWH [There is strong evidence that adults with higher body fat are at increased risk of type 2 diabetes and cardiovascular disease [Individuals in profiles 6 and 7, those thin and stunted, from the IMVASK cohort (where dietary intake was recorded) tended to report lower dairy consumption than other profiles. It is not possible to ascertain a causal link between lower dairy consumption and lower anthropometric Z-scores in this dataset because growth and diet have been collected contemporaneously. However, given that dairy consumption is associated with linear growth in adolescence [Our study has limitations. We used the UK 1990 reference equations, which might be considered out-of-date compared to the WHO reference, although they do provide WA Z-scores for those aged 0 to 23 (allowing the inclusion of 20-year-olds at follow-up), where the WHO has an upper limit of age 10. However, the choice of reference is not critical for our aim to compare between groups within our population, and we encompassed the full range of growth faltering including WA, HA and BMI together using the British standards. Our sample has over-representation of CWH with comorbidity (which could have included some enrolled into the IMVASK study where FEV1 was not measured), so we were unable to provide estimates of the population prevalence of our growth profiles. On the other hand, because those with chronic conditions were over-represented, we were able to differentiate between two profiles which both constitute those thin and stunted, given the high prevalence of growth faltering among CWH with co-morbid CLD from the BREATHE RCT. We had 16% loss to follow-up overall and this was related to factors which are also associated with growth profile [The wide age range of our study, longitudinal nature, robust statistical methods, and ability to compare three groups (HIV-negative children, CWH, and CWH with co-morbid CLD), the majority of whom are from the same population, are strengths of our study. We had a limited number of variables which were common across studies and so were constrained in our ability to identify factors associated with growth profiles. However, we provide a framework for exploring growth faltering among adolescents and have identified the most vulnerable in terms of those having weight and height 3 SD below UK population norms.