ABSTRACT
The incidence of newly-diagnosed Insulin-dependent diabetes mellitus (IDDM) in a pediatric population has been found to increase with colder seasons in countries at latitudes where a marked weather change presumably triggers a higher prevalence of viral infections (especially respiratory), that may induce an insulitis which could be etiologically related with IDDM. In order to assess whether the apposite is true for a country with rather uniform climate, like Puerto Rico, we have studied the seasonal pattern of newly diagnosed IDDM seen at our institution during a 10 year period (1973-1982). also, recent reports on a higher mortality from diabetes in Puerto Rico going from 16.6 in 1977 to 31.0 in 1983, prompted us to look at a possible secular trend of increasing incidence of IDDM. There were a total of 269 new cases of IDDM or 27 cases/year, with standard deviation (SD) of ñ 5.3, range 18 to 33, and no secular trend at all. Sex distribution was quite variable, having male: female (m/f) ratios from 1:2 to 3:1, and an over-all m/f of 13.3/13.6. Incidence of IDDM per month of year went from a low of 1.7 for April and November to a high of 3.0 for March and 2.9 for September, 2.8 for October, with a mean of 2.21 ñ 0.48 cases/month. Again, no significant seasonal differences were noted. Mean incidence for our "cold" months (November to April was 2.25/month; for our "hot" seson (May to October) was 2.3/month; for our "rainy" season (July to December) 2.3 and for our "dry" season (January to April) 2.3/month. Thus, it appears that there are no such seasonal trends of IDDM In Puerto Rico