Multiple sclerosis and solar exposure before the age of 15 years: case-control study in Cuba, Martinique and Sicily.

Few studies report a protective role of childhood solar exposure to multiple sclerosis. Our objective was to confirm the protective role of childhood solar exposure in multiple sclerosis in Cuba, Martinique and Sicily. This was a matched case- control study, and cases met Poser criteria for clinically, laboratory (definite, probable) multiple sclerosis. Controls were resident population, without neurological disorder, living close to cases (within 100 km), matched for sex, age (+/-5 years), residence before age 15. We recruited 551 subjects during a 1-year period (193 cases, Cuba n = 95, Sicily n = 50, Martinique n = 48; 358 controls). Some (89%) met definite clinical multiple sclerosis criteria (relapsing remitting form (with and without sequel) (74%), secondary progressive (21%), primary progressive (5%)). Odds ratios in a uni-variate analysis were: family history of multiple sclerosis (5.1) and autoimmune disorder (4.0); wearing shirt (3.5), hat (2.7), pants (2.4); sun exposure causing sunburn (1.8); sun exposure duration (1 h more/day; weekends 0.91, weekdays 0.86); bare-chested (0.6); water sports (0.2). Independent factors in the multivariate analysis were family history of multiple sclerosis (4.8 (1.50-15.10)), wearing pants under sunlight (1.9 (1.10-3.20)), sun exposure duration (1 h more/ day, weekdays 0.90 (0.85-0.98), weekends 0.93 (0.87-0.99)), water sports (0.23 (0.13-0.40)). We conclude that outdoor leisure activities in addition to sun exposure reports are associated with a reduced multiple sclerosis risk, with evidence of dose response.

Incidence and prevalence of amyotrophic lateral sclerosis in Uruguay: a population-based study.

OBJECTIVE: To determine the incidence and prevalence of amyotrophic lateral sclerosis (ALS) in the Republic of Uruguay. METHODS: The study was performed in Uruguay (3,241,003 inhabitants) during a 2-year period (2002-2003). To ensure complete case ascertainment, multiple sources of information were used, including all the neurologists, other medical specialties, general physicians, neurophysiology laboratories, hospital medical records and death certificates. ALS diagnosis was based on El Escorial criteria. Although all patients with motor neuron disease were enrolled in the follow-up, only probable and definite cases are included in the study. RESULTS: Between January 1st, 2002, and December 31st, 2003, 89 new patients were diagnosed with probable or definite ALS. The mean annual incidence rate was 1.37 per 100,000 persons. The incidence was higher for men (1.95) than for women (0.84) with a male to female ratio of 2:1. For both, the incidence increased throughout the years showing a peak in the 65-74 age group among men and the 55-64 age group among women. Mean age at onset of ALS disease was 58.7 years. The estimated mean annual incidence for ALS calculated by the capture recapture method was 1.42 (95% CI, 1.13-1.72). On December 31st, 2002, the crude prevalence was 1.9 per 100,000 inhabitants. CONCLUSIONS: ALS incidence is within a narrow range across countries despite the genetic, environmental and socioeconomic differences when similar prospective design, diagnosis criteria and data analyses are applied.