EMPIRICAL ESTIMATION OF RECURRENCE RISKS IN DISEASES WITH VARIABLE AGE-AT-ONSET (VOL 27, PG 1648, 1991)

Combinatorial approach in empirical estimation of recurrence risks in variable age-at-onset (AO) was elaborated in [2], where special combin atorial coefficient was introduced, the so called ''constrained polyno mial coefficient'', which permit to count the permutations of AO-sibli ng classes, constrained by their age to the time of study (ATS). Unfor tunately giving account of method of calculation m(d) - the table morb idity rate - for siblings of age d in [2] were not introduced limitati ons for AO or ATS of those siblings, which were affected before or not yet reached the age d under evalution. Lack of the limitations result in the estimate of prevalence (i.e. the proportion of affected siblin gs, with the given AO, among all the siblings), but not incidence or a ge-specific morbidity rate (i.e. the proportion of the siblings, affec ted in the d-th age interval among those siblings, who reached and/or outlive the age d, being free of disease before the age d under evalua tion). In this communication the oversight is removed and the method o f calculation of m(d) is simplified: only the two classes instead of a lot of the possible AO-classes of siblings are considered, namely - ' 'affected in the d-th age interval'' and ''health in the d-th age inte rval'' under evaluation. Thus, the way of calculation Of m(d) May be r educed to the simple binomial case.