Effect of hearing impairment on educational outcomes and employment up to the age of 25 years in northern Finland.

The association between hearing impairment in adolescence and school performance and the outcome of education was studied among 25-year-old subjects followed since pregnancy in the Northern Finland birth cohort. The series, 395 subjects with abnormal hearing and 977 randomly selected controls, was based on a questionnaire on hearing and school achievement sent to 11780 members of the cohort alive at the age of 14 years, and on audiometric screening test requested from health centers. Hearing loss was defined as 'clinically significant' if the pure tone average (PTA; mean of the thresholds at 0.5, 1 and 2 kHz) exceeded 25 dB in the better ear; a threshold of > or = 30 dB at 4 kHz and a PTA of < or = 25 dB as '4 kHz loss'; and as 'slightly abnormal' if any of the thresholds exceeded 20 dB at any frequency and the case did not belong to the above two categories. The more severe the hearing impairment, the poorer was the child's performance at elementary school. Those with normal hearing and those with a slightly abnormal or 4 kHz loss were equally often accepted for intermediate education (88%), while those with a clinically significant loss had the lowest acceptance figures (64%). When adjusting for neurological and social confounders, excluding mental disability, the risk of not qualifying from intermediate or higher education at all was twice as high among those with a clinically significant loss as among the controls (OR 2.1, 95% CI 1.13-3.8), and was still elevated after adjustment had been made for all the relevant perinatal, neurological and social factors (OR 1.9, 95% CI 1.02-3.6). 14% of those with a clinically significant hearing loss, 9% of the subjects with a 4 kHz loss and 7% of those with normal hearing were unemployed at the age of 25 years. Hearing impairment appears to have effects on both the outcome of education and employment status.

The development of myopia up to the age of twenty and a comparison of refraction in parents and children.

As a part of a longitudinal birth cohort study, refraction was measured at the age of 20 years in 236 persons known to have had myopia at the age of 14 years and 266 controls (2982 refractions). The earlier the myopia had started, the more myopic the eyes were at the age of 20 years. The greatest mean refraction values, -4.94 D for males and -6.62 D for females were found when the change to myopia had started before the age of 10. The mean progression of myopia (the mean progression curves were achieved by calculating the mean refraction values at different ages) seems to continue at least to the age of 20. A female child with a myopic mother is more likely to develop myopia than a female child with a non-myopic mother and the same relation holds good between a male child and his father. The myopic refractive error seems to be greater in the children than in their parents.