Ethnic differences in the prevalence of high homocysteine levels among low-income rural Kazakh and Uyghur adults in far western China and its implications for preventive public health.

OBJECTIVE

Homocysteine (Hcy) is a relevant biomarker of vascular disease: serum Hcy concentrations will increase the risk of systolic hypertension, whereas hyperhomocysteinemia (HHcy) has a synergistic effect with hypertension and increases the risk of cardiovascular disease. However, information has primarily been gathered from high-income and urban settings, and little is known regarding low-income rural settings. This study focused on a low-income rural and nomadic minority residing in far western China. Hcy levels were tested, and the prevalences of HHcy and H-type hypertension were investigated in this population.

METHODS

This study used a stratified cluster random sampling method, selecting 2,180 individuals as subjects from Kazakh and Uyghur inhabitants (≥25 years old) of 18 villages in Xinjiang, China, which is approximately 4407 km from the capital, Beijing. Hcy levels were determined using a double reagent enzymatic cycling method. HHcy (Hcy > 10 μmol/L) was defined by the criteria of the American Heart Association.

RESULTS

The Kazakh geometrical mean of Hcy was 13.34 μmol/L, and the Uyghur mean was 13.75 μmol/L; the mean values were higher in males than in females of both ethnicities (15.99 μmol/L vs. 11.63 μmol/L; 15.71 μmol/L vs. 11.91 μmol/L, respectively, p < 0.01). The serum levels of Hcy increased with increasing age in both ethnicities, and except for Kazakh individuals >65 years old, Hcy serum levels were higher in males than in females in all age groups of both ethnicities, with a p value less than 0.01. The Kazakh prevalence of HHcy was 80.0%, and the Uyghur prevalence was 78.2%; the male prevalence was higher than that in females for both ethnicities (93.5% vs. 69.6%; 90.8% vs. 64.6%, respectively, p < 0.05). Among the Kazakh, the prevalence of hypertension was 35.1%, and the prevalence was higher in males than in females (44.3% vs. 28.1%, p < 0.001); 87.6% of the Kazakh individuals had H-type hypertension, and the prevalence was higher in males than in females (95.0% vs. 80.0%, p < 0.05). In Uyghur, the prevalence of hypertension was 30.6%, and the prevalence was higher in males than in females (37.9% vs. 22.8%, p < 0.001); 88.0% of the Uyghur individuals had H-type hypertension, and the prevalence was higher in males than in females (93.9% vs. 79.1%, p < 0.05).

CONCLUSIONS

HHcy was found to be common among the Kazakh and Uyghur. The prevalences of HHcy and H-type hypertension were high among both ethnicities and differed depending on gender and age. Community interventions should be conducted to improve public health conditions among the Kazakh and Uyghur in Xinjiang.