摘要目的 观察低氟砖茶的人群干预效果,为饮茶型地方性氟中毒的预防控制提供参考.方法 在甘肃省阿克塞县饮茶型地方性氟中毒霞病区.选取有5～12岁儿童的哈萨克族家庭86户,分成两组:46户为干预组,投放低氟砖茶;40户为对照组,仍饮普通砖茶.在干预前及干预期间,监测干预组、对照组饮水、茶水、砖茶、尿的含氟量,通过茶水含氟量计算干预组、对照组成人和儿童日均总摄氟量;干预前对8～15岁在校哈萨克族儿童进行氟斑牙患病情况基线调查,干预结束后对干预组、对照组儿童进行氟斑牙检查.饮水、茶水、砖茶及尿液样品含氟量测定采用离子选择电极法,氟斑牙诊断采用Dean法.结果 干预前、干预42个月时,居民饮水含氟量分别为0.36、0.50 mg/L.成人及儿童日总摄氟量,干预组(成人:4.39、5.12、5.38、4.49 mg,儿童:1.90、2.23、2.33、1.94 mg),明显低于对照组(成人:8.42、9.07、8.35、7.92,儿童:3.65、3.93、3.62、3.43 mg).监测低氟砖茶、市售砖茶各4批,4批低氟砖茶平均含氟量除第2批(530.4 mg/kg)较高外、其余3批(239.3、222.88、154.7mg/kg)均低于市售砖茶(366.9、412.2、286.0、379.6 mg/kg),4批共21份低氟茶样中有16份含氟量符合茶氟国家标准(<300 mg/kg),合格率为76.19%(16/21),4批市售砖茶21份茶样只有5份合格,合格率为23.80%(5/21),两组比较差异有统计学意义(χ2=11.52,P<0.01).干预12、36、42个月时,干预组成人(1.84、1.23、1.77 mg/L)和儿童尿氟(1.55、0.65、1.10 mg/L)均低于对照组(成人:3.37、3.68、3.02 mg/L,儿童:2.64、1.64、2.62mg/L),二者比较差异均有统计学意义(t值分别为2.94、2.43,3.91、3.29,2.31、4.42,P<0.01或<0.05).儿童氟斑牙基线调查的检}H率为69.02%(127/184),干预后干预组儿童氟斑牙检出率[44.83%(13/29)]明显低于对照组[71.88%(23/32);χ2=4.60,P<0.05].结论 饮低氟砖茶可降低饮砖茶人群总氟摄入量,减轻机体氟负荷和高氟危害.

abstractsObjective To evaluate the intervention effects of low-fluoride brick tea in the population, and to provide data for the prevention and control of the brick-tea type fluorosis. Methods Eighty-six Kazakh families with 5-12 years old children were selected and divided into two groups in the severe brick-tea type fluorosis areas of Akesai County of Gansu Province. Forty-six households were intervened by drinking low-fluoride brick tea as intervention group and another 40 households drank general brick tea as control group. The fluoride content in water, tea and urine was monitored and the total daily fluoride intake of adults and children was calculated by the fluoride content of the tea before and during intervention. The baseline prevalence of dental fluorosis was surveyed in all Kazakh school students aged 5 - 12 years before intervention, dental fluorosis prevalence were surveyed in two groups after the intervention. The fluoride content in water, urine,tea, and brick-tea samples was detected by iron electrode method, and dental fluorosis was diagnosed by Dean's method. Results The fluoride content of water were 0.36,0.50 mg/L respectively before and 42 months after intervention. The total daily fluoride intake of adults and children in the intervention group (being 4.39,5.12,5.38,4.49 mg in adults and 1.90,2.33 in children, 2.33, 1.94 mg for four calculations) were lower than those in control group (8.42,9.07,8.35,7.92 and 3.65,3.93, 3.62,3.43 mg). Except the second batch (530.4 mg/kg), the average fluoride content of the other 3 batches of low-fluoride brick tea(239.3,222.88,154.7 mg/kg) was lower than that of 4 batches of market brick tea(366.9,412.2, 286.0,379.6 mg/kg). The fluoride content of low-fluoride brick tea samples was in accordance with the national standard(< 300 mg/kg) in 16 of 21 samples in 4 the batches, and the qualifying rate was 76.19%(16/21). Only 5 of 21 market brick tea samples in 4 batches was qualified, accounting for 23.80%(5/21), both were significantly different(χ2= 11.52, P < 0.01). In 12, 36, 42 months after intervention, urine fluoride content in the intervention group of adult(1.84,1.23,1.77 mg/L) and children(1.55,0.65,1.10 mg/L) was less than that of the control group (adults: 3.37,3.68,3.02 mg/L, children: 2.64,1.64,2.62 mg/L), both being statistically significant (t value were 2.94,2.43,3.91,3.29,2.31,4.42, P < 0.01 or 0.05). The detective rate of dental fluorosis was 69.02%(127/184)at baseline among children. After the intervention, it lowered to [44.83% (13/29) in the intervention group, significantly lower than that in the control group[71.88%(23/32), χ2 = 4.60, P < 0.05]. Conclusion Low-fluoride brick tea can reduce the fluoride intake of the residents who drink brick tea, and alleviate excessive fluoride and the damage of high-fluoride.