Secretor status and dental caries in Iceland.

The proportion of non-secretors of ABH blood-group substances among Icelanders is one of the highest recorded for European countries. Dental caries prevalence is also very high. In this study of dental caries in young adults mean number of decayed, missing and filled teeth for secretors were 17.4 and for non-secretors 19.9 (P less than 0.05). A majority of patients seeking free dental treatment in the Dental School were non-secretors (62.7%) significantly more than the proportion of non-secretors in the general population (36%; P less than 0.01). It is postulated that blood group substances may interfere with the adherence of Streptococcus mutans to teeth.