Age-specific incidence and prevalence rates of treated epilepsy in an unselected population of 2052922 and age-specific fertility rates of women withepilepsy

Background There are no data on prevalence or incidence of treated epilepsy , and no data on fertility of women with epilepsy from an unselected UK pop ulation. Methods We used the General Practice Research Database to ascertain the inc idence and prevalence of people with treated epilepsy in an unselected popu lation of 2 052 922 people in England and Wales, and also age-specific fert ility rates. We defined period prevalence of treated epilepsy as the number of people with epilepsy taking an antiepileptic drug per 100 000 people du ring 1995. The incidence of treated epilepsy was defined as the number of n ew cases of treated epilepsy per 100 000 people during the same period. We calculated fertility rates among women with treated epilepsy between 1991 a nd 1995 and compared these rates with the population rates for England and Wales in 1993. Findings The period prevalence of treated epilepsy in 1995 was 5.15 per 100 0 people (95% CI 5.05-5.25). The prevalence was lower in children (age 5-9 years 3.16 [2.86-3.48]; 10-14 years 4.05 [3.70-4.42]), and higher in older people (65-69 years 6.01 [5.50-6.57]; 70-74 years 6.53 [5.97-7.14]; 75-79 y ears 7.39 [6.73-8.11]); 80-84 years 7.54 [6.78-8.39]; 85 years and older 7. 73 [6.98-8.66]. The incidence of treated epilepsy was 80.8 per 100 000 peop le (76.9-84.7). The incidence was lower in children (5-9 years 63.2 [50.5-7 9.1]; 10-14 years 53.8 [42.4-68.31) and higher in older people (65-69 years 85.9 [68.5-107.3]; 70-74 years 82.8 [65.0-105.2]; 75-79 years 114.5 [116.9 -179.2]; 80-84 years 159 [125.2-202.6]; greater than or equal to 85 years 1 35.4 [100.4-178.7]). Fertility was lower among women with treated epilepsy, with an overall rate of 47.1 livebirths per 1000 women aged 15-44 per year (42.3-52.2), compared with a national rate of 62.6 in the same age-group. The standardised fertility ratios were significantly lower between the ages of 25 and 39 years in women with epilepsy (p<0.001). Interpretation Compared with previous studies, we found that the incidence of epilepsy was higher in elderly people and lower in children. The prevale nce rates also increase with age. Women aged 25-39 years with treated epile psy have significantly lower fertility rates than those in the general popu lation. Research is needed to identify any potentially preventable causes f or the low fertility rates.