Incidence of acquired primary hypolactasia in three New Zealand racial groups.

The relative frequency of acquired primary hypolactasia has been determined in adult Maoris, Samoans and Europeans by measuring an alteration in breath hydrogen concentration two hours after a 50 g oral lactose load. By this indirect measurement hypolactasia was present in 64% of Maoris, 54% of Samoans and 9% of Europeans. The differences between Maoris and Europeans (p less than 0.001) and between Samoans and Europeans (p less than 0.001) were significant.