Geographical distribution of optic nerve hypoplasia and septo-optic dysplasia in Northwest England.

OBJECTIVE

To study the distribution of septo-optic dysplasia (SOD) and optic nerve hypoplasia (ONH) in the Greater Manchester and Lancashire (GM&L) region of Northwest England, and to analyze occurrence by location and over time.

STUDY

DESIGN

A population-based incidence study was undertaken for cases of SOD/ONH from GM&L. Standardized incidence ratio (SIR) for each district, relationships between SIRs and possible geographically varying risk factors, and spatial and space-time clustering were analyzed.

RESULTS

Eighty-seven cases had a confirmed diagnosis of ONH/SOD giving an incidence of 10.9/100,000 per year in GM&L. SIRs ranged widely but were significantly elevated (lower confidence limit >100) in three districts: 167%, 192%, and 198%, respectively. All three were high population density, inner-city locations. SIRs were significantly correlated with higher rates of unemployment (r = 0.49, P = .01), dependent children in non-earning households (r = 0.47, P = .02), underage conceptions (r = 0.46, P = .02), and underage pregnancies (r = 0.44, P = .03). There was no evidence of spatial or space-time clustering.

CONCLUSIONS

The incidence of ONH/SOD in GM&L was higher than that reported elsewhere. Cases were more common in areas that had higher unemployment and teenage pregnancy rates.