title: Comparison of histamine and methacholine for use in bronchial challenge tests in community studies.
abstract: Measurement of bronchial reactivity is widely used in epidemiological surveys. Histamine has been compared with methacholine inhalation challenge in two samples of adults from a small town to determine which is the better agent for use in community studies. Increasing doses of histamine and methacholine were given, up to a maximum of 4 and 12 mumol respectively, according to the method of Yan et al, the provocative dose of agonist causing a 20% fall in FEV1 (PD20) being measured. More subjects had a measurable PD20 with methacholine than with histamine, both in a random sample of 108 subjects (25 v 11 subjects, p less than 0.01) and in an additional 95 subjects selected because of wheeze in the last 12 months (67 v 48 subjects, p less than 0.01). Side effects were mild with both agents but histamine caused voice change in more subjects (21% v 11%). Repeatability was assessed in a further group of subjects with wheeze in the last year. The 95% range for a single estimation of PD20 in subjects with a measured PD20 on at least one occasion was +/- 2.5 doubling doses for histamine (n = 25) and +/- 2.1 doubling doses for methacholine (n = 33). Thus methacholine has advantages over histamine for community studies of bronchial reactivity as it is possible to use doses that produce more PD20 measurements with fewer side effects.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001985:Bronchial Provocation Tests / Q000379:methods*; D004812:Epidemiologic Methods; D005541:Forced Expiratory Volume; D006632:Histamine; D006801:Humans; D016210:Methacholine Chloride; D008688:Methacholine Compounds; D008875:Middle Aged; D011897:Random Allocation
chemical_list: D008688:Methacholine Compounds; D016210:Methacholine Chloride; D006632:Histamine