在挪威麻风发病率迅速下降期间观察到发病年龄一致上升。同一时期新病例的性别和病型分布也发现长期趋势。近年在麻风病发病率已下降的国家也观察到类似趋势。这些观察要求阐明在发病率迅速下降的情况下可能是带有普遍性的流行病学类型。本文试图阐明观察到长期变化的流行病学背景,集中在麻风病发病率正在下降的任一地区是否可预期出现类似的变化。 A consistent rise in age of onset was observed during the rapid decline in the incidence of leprosy in Norway. Long-term trends were also found in the gender and disease distribution of new cases during the same period. Similar trends have also been observed in countries where the incidence of leprosy has declined in recent years. These observations call for elucidation of the likely prevalence of epidemiological patterns in the context of a rapidly declining incidence. This article attempts to elucidate the epidemiological context in which long-term changes have been observed and whether similar changes can be expected in any area where the incidence of leprosy is declining.