Respiratory conditions, including asthma, and height in primary school.

The National Study of Health and Growth (NSHG) of primary school children has examined the relationships between height and each of six separate respiratory conditions, one of which was asthma, in children aged 5-11 years, allowing for a number of genetic and environmental confounding factors, in particular for parental height. The relationships were investigated in a 'representative' sample of 4974 Caucasian English children in 1984 and in an 'ethnic/inner city' sample of 3419 Afro-Caribbean/Indian and Pakistani/Caucasian English children in 1985. None of the respiratory conditions was found to be related to height except for 'wheeze most days', whether or not it was accompanied by an asthma attack in the last 12 months. The Caucasian children in the 'representative' sample who had 'wheeze most days', were 0.17 height standard deviation score (95% confidence interval 0.03 to 0.31) less (approximately 1 cm) than those with no wheeze. Comparisons with previous results for NSHG 'representative' Caucasian English children in 1973 showed good agreement except for children with three or more asthma attacks who were found to be shorter in 1973, but not in 1984, which may reflect improved treatment, or milder asthma being reported in 1984. It was concluded that, in the 1980s, the respiratory conditions were not related to height. The exception was 'wheeze most days'. It is suggested that this is an indicator of sickness, most likely asthma, which is being experienced with sufficient severity to affect growth slightly.