Thiamine deficiency is associated with ethnicity in a subtropical area of China

Clinical signs which probably indicate thiamine (vitamin B1) deficiency have been evident in the Meng Ding District of Yunnan province, China for decades. In 1990, 5979 people were surveyed using cluster sampling to investigate the association of signs of thiamine deficiency with potential causative factors. Data on past and present symptoms of thiamine deficiency were collected from individual subjects, hospital records and health care personnel. Information on staple food intake over the previous three months was collected from both individual subjects and from commune administrations. Signs of thiamine deficiency occurred most often in the Dai ethnic group. 5.1% of Dai males and 6.6% of Dai females had met criteria for thiamine deficiency at some time over the previous 7 years. In other ethnic groups, signs of thiamine deficiency occurred in only 0. 1% of males and 0.2% of females over the same time period. The incidence of signs of thiamine deficiency did not vary with time during the 7 years prior to the survey, however the condition appeared to be more severe (resulting in more cases of hospitalization) in 1983-1985. Signs of thiamine deficiency showed a seasonal distribution with the highest rates occurring in the hot, dry season. Signs of thiamine deficiency were common among Dai women after childbirth. The findings indicate that thiamine deficiency is strongly associated with ethnicity in this population. It is likely that thiamine undernutrition is associated with dietary intake and practices which differ by ethnic group. Public health measures to minimize thiamine undernutrition in the Dai group include education and supplementation.