Meloni T, Colombo C, Ruggiu G, Dessena M, Meloni G F
Department of Paediatrics and Neonatology, University of Sassari, Italy.
Ital J Gastroenterol Hepatol. 1998 Oct;30(5):490-3.
It has recently been suggested that primary lactase deficiency might have been selected for by malaria, as occurred for beta-thalassaemia and glucose 6-phosphate dehydrogenase deficiency. However, recently we have found that the prevalence of primary lactase deficiency in the area of Sassari (Northern Sardinia), where, in the past, there was intermediate malarial endemicity, is comparable to that observed in the adult population from other areas of Southern Italy where malaria was less endemic.
To address the problem further, we have determined the prevalence of primary lactase deficiency, glucose 6-phosphate dehydrogenase deficiency deficiency and beta-thalassaemia trait in the populations of three Sardinian villages which differ in altitude above sea-level, socioeconomic features, history of endemic malaria and prevalence of b-thalassaemia and glucose 6-phosphate dehydrogenase deficiency.
We tested 138 adult males: 53 were from Fonni (a non-malarial mountain village, with a strong pastoral tradition), 38 from Lodé (a village with a similar pastoral tradition, but high malarial endemicity in the past) and 47 from Terralba (a lowland fishing village with an agricultural tradition and heavy malarial morbidity and mortality).
A blood sample was obtained in all subjects for determination of HbA2 and glucose 6-phosphate dehydrogenase activity. Lactase deficiency was assessed by measuring breath hydrogen production after oral administration of lactose (50 g), by gas-chromatography.
The frequencies of glucose 6-phosphate dehydrogenase deficiency and of beta-thalassaemia trait in the non-malarial village of Fonni were strikingly low, compared to frequencies found in the two villages (Terralba and Lodé) with a very high past malarial morbidity. In contrast, there was no significant difference in the prevalence of lactase deficiency in the three groups of subjects from the three villages.
These data obtained in Northern Sardinia do not support the hypothesis of a selection of primary lactase deficiency by malaria. For definitive conclusions, however, the malaria hypothesis should be tested in other parts of the world.
最近有人提出，原发性乳糖酶缺乏症可能像β地中海贫血和葡萄糖-6-磷酸脱氢酶缺乏症那样，是由疟疾选择出来的。然而，最近我们发现，在过去疟疾呈中度流行的萨萨里地区（撒丁岛北部），原发性乳糖酶缺乏症的患病率与意大利南部其他疟疾流行程度较低地区的成年人群中观察到的患病率相当。
为了进一步解决这个问题，我们测定了三个撒丁岛村庄人群中原发性乳糖酶缺乏症、葡萄糖-6-磷酸脱氢酶缺乏症和β地中海贫血特征的患病率，这三个村庄在海拔高度、社会经济特征、疟疾流行病史以及β地中海贫血和葡萄糖-6-磷酸脱氢酶缺乏症的患病率方面存在差异。
我们对138名成年男性进行了检测：53名来自丰尼（一个非疟疾流行的山村，有浓厚的畜牧传统），38名来自洛德（一个有类似畜牧传统但过去疟疾高度流行的村庄），47名来自泰拉巴（一个有农业传统且疟疾发病率和死亡率很高的低地渔村）。
采集所有受试者的血样以测定HbA2和葡萄糖-6-磷酸脱氢酶活性。通过气相色谱法测量口服乳糖（50克）后呼出氢气的产生量来评估乳糖酶缺乏症。
与过去疟疾发病率非常高的两个村庄（泰拉巴和洛德）相比，非疟疾流行的丰尼村葡萄糖-6-磷酸脱氢酶缺乏症和β地中海贫血特征的发生率极低。相比之下，来自三个村庄的三组受试者中乳糖酶缺乏症的患病率没有显著差异。
在撒丁岛北部获得的这些数据不支持疟疾选择原发性乳糖酶缺乏症的假说。然而，为得出明确结论，应在世界其他地区对疟疾假说进行检验。
