Risk factors related to deaf-mutism among pupils attending the Alexandria governmental deaf-mute schools

Childhood deafness interferes with the cognitive development of the child, so it is considered a major handicap. The present work was carried out to reveal possible risk factors of deaf-mutism and the magnitude of each. The case control design was chosen as a research methodology. A 50% sample of deaf-mute pupils at the primary level were selected at random from each of the two governmental schools for the deaf-mutes in Alexandria (boys=96, & girls=76). A control group chosen at random from a main stream governmental school and matched by age and sex of the pupils as well as with education and occupation of the father. Matching was carried out at the sampling phase, pairing each case to its control. Data were collected by interviewing the mothers using an interviewing schedule. Matched analysis was carried out where pairing of cases and controls was retained. The likelihood estimate of Odds ratio conditional on the number of discordant pairs was estimated using McNemer's test. The 5% level was chosen as the level of significance. The study revealed 172 deaf-mute pupils. Their mean age was 9.48+/-1.981 years. Boys outnumbered girls (55.8% and 44.2% respectively). In 59.4% parents were cousins. Deafness was first noticed at 6 to 60 months of age with a mean of 14.70+/-10.2 months. Most fathers and mothers were illiterate (48.84% and 61.63%). Heredity was a risk factor, where 84.82% of cases had a positive family history compared to none of the controls. Moreover, in case of consanguinity the Odds ratio=5.60. Acquired deafness constituted the second important group of all causes of deafness. Meningitis featured as the most important cause of acquired deafness with an estimated relative risk of 18.5, followed by fever (Odds ratio=4.67), then repeated attacks of acute tonsillitis and ear disease where the case control percent difference was 8.72% and 4.65% respectively.