These prevalence estimates should be considered minimum prevalence.Even so, these figures are
similar to recent reports from the United Kingdom and the United States.For example, the combined Chakrabarti and Fombonne (2001, 2005) studies reported autism prevalance of ~19/10,000 and autistic spectrum prevalence of ~61/10,000. Very similar figures from the UK were recently found by Williams et al. (2008). In fact the reported minimum autistic spectrum prevalence in Aruba is noticeably similar to reported autistic spectrum prevalence in the Faroe Islands (~56/10,000; Ellefsen et al., 2007).
I am no climatologist, but all available reports converge on Aruba, which sits not too far from the equator, being a remarkably sunny and dry place. This is not the case for the Faroe Islands, which have a cloudy, rainy, foggy climate where sunshine is rare.
Speculation that lack of sun exposure may cause autism via Vitamin D deficiency is back in the media, providing a reminder that Michael Waldman and his Cornell colleagues persist in claiming that less precipitation means fewer autistics. Aruba's recent autism epidemiology sheds some bright light on these hypotheses.
Chakrabarti, S., & Fombonne, E. (2001). Pervasive developmental disorders in preschool children. JAMA, 285, 3093-9.
Chakrabarti, S., & Fombonne, E. (2005). Pervasive developmental disorders in preschool children: Confirmation of high prevalence. American Journal of Psychiatry, 162, 1133-41.
Ellefsen, A., Kampmann, H., Billstedt, E., Gillberg, I.C., & Gillberg, C. (2007). Autism in the Faroe Islands: an epidemiological study. Journal of Autism and Developmental Disorders, 37, 437-44.
Balkom, I., Bresnahan, M., Vogtländer, M., Hoeken, D., Minderaa, R., Susser, E., & Hoek, H. (2009). Prevalence of treated autism spectrum disorders in Aruba Journal of Neurodevelopmental Disorders DOI: 10.1007/s11689-009-9011-1
Waldman, M., Nicholson, S., Adilov, N., & Williams, J. (2008). Autism prevalence and precipitation rates in California, Oregon, and Washington counties. Archives of Pediatrics and Adolescent Medicine, 162, 1026-34.
Williams, E., Thomas, K., Sidebotham, H., & Emond, A. (2008). Prevalence and characteristics of autistic spectrum disorders in the ALSPAC cohort. Developmental Medicine and Child Neurology, 50, 672-677.