Multiple Sclerosis in Italy: A 40-Year Follow-Up of the Prevalence in Ferrara.

BACKGROUND: To assess a longitudinal follow-up of the prevalence of multiple sclerosis (MS) through 4 decades in the province of Ferrara, northern Italy, and reappraise the current rates on December 31, 2016.

METHODS: We conducted a community-based intensive prevalence study, by adopting a complete enumeration approach. MS cases were identified from administrative health data and medical records from the Units of Neurology and Motor Rehabilitation, Ferrara University Hospital, from other provincial neurological structures and from archives of the National Pension Institute and National Health Insurance scheme of the study area. Case ascertainment method and case definition are analogous to those adopted in previous surveys in the same area of study.

RESULTS: On December 31, 2016, 685 patients (478 women and 207 men) affected by definite or probable MS (Poser's criteria) were living in the province of Ferrara (population 386,896), yielding a crude prevalence ratio of 194.91 (95% CI 180.4-209.6) per 100,000, 260.8 (95% CI 238.10-285.82) for women and 123.1 (95% CI 106.98-141.21) for men The prevalence ratio was 26.9 per 100,000 in 1978, increased to a value of 46.1 per 100,000 in 1981, 69.4 per 100,000 in 1993, 120.9 per 100,000 in 2004. Female to male ratio was 2.31 (1.2 on December 31, 1978). The mean duration of the disease at prevalence day was 17.5 ± 11.9 years (13.9 ± 10.8 years in 1978). The mean age at prevalence day was 52.04 ± 10.8 years (13.8 ± 10.8 years in 1978).

CONCLUSION: Our study has confirmed the province of Ferrara is an area at high risk for MS, in line with epidemiological data from the regions of continental and insular Italy. The sharp increase in MS prevalence over time in this population can be imputed in part to a greater exposition to risk factors in genetically susceptible subjects but also to an increased survival and improved ascertainment. So, the results suggest that both methodologic and environmental factors are essential in determining the real distribution of MS. The need to get reliable estimates of MS prevalence must be highlighted as a public health and research priority, essential to support planning and prioritization of care services and to reduce the overall burden of chronic disease.