Ethnicity Modifies the Relationship between FPG and HbA1c in Singaporeans
Year: 2011
Abstract Number: 1005-P
Authors: KAVITA VENKATARAMAN, ERIC Y. KHOO, AGUS SALIM, JEANNETTE J. LEE, A.-C. THAI, E.-S. TAI
Institutions: Singapore, Singapore
Results: There are substantial inter-individual variation in glycated hemoglobin (HbA1c) especially among individuals of different races and ethnic groups. We studied whether HbA1c was significantly different among the Chinese, Malay and Indian population in Singapore. A sample of 3897 individuals, without known diabetes (DM), were selected from a cross-sectional study (Singapore Prospective Study). All subjects underwent a detailed interview, physical examination, including anthropometric and blood sampling for biochemical evaluation. Descriptive analysis, Pearson's correlation, analysis of variance and multiple linear regression analyses were used to examine the influence of ethnicity on HbA1c. Mean unadjusted HbA1c was highest among Indians (6.09%), followed by Malays (5.96%) and Chinese (5.76%) (p<0.05). After adjustment for fasting plasma glucose (FPG), age, gender, waist circumference, serum cholesterol, serum triglyceride, and HOMA IR, HbA1c was still significantly different between Indian and Chinese ethnicities though the magnitude of difference was small (0.06%, p<0.05).
| HbA1c |
Chinese (n=2697) |
Malay (n=633) |
Indian (n=565) |
| Mean |
5.76(0.013) |
5.96(0.045) |
6.09(0.046) |
| Adjusted mean |
5.83(0.01) |
5.85(0.02) |
5.89(0.022) |
There were significant interaction effects between ethnicity and FPG in the multiple regression model for HbA1c such that for the same increase in FPG, HbA1C showed a greater increase in Indians and Malays (p<0.001).
| Variables in model |
B |
p |
| Age |
0.005 |
<0.001 |
| Female |
0.085 |
<0.001 |
| Indian |
0.055 |
0.02 |
| Malay |
0.005 |
0.81 |
| FPG(centred) |
0.493 |
<0.001 |
| Waist circumference |
0.004 |
<0.001 |
| S.cholesterol |
0.033 |
<0.001 |
| Indian*FPG |
0.066 |
<0.001 |
| Malay*FPG |
0.133 |
<0.001 |
Indians and Malays had higher HbA1c compared to Chinese with FPG accounting for most of this difference. There was, however, significant interaction between ethnicity and FPG in determining HbA1c values, with weaker association between HbA1c and FPG in Chinese compared to Indians and Malays. Understanding the biological basis of this interaction could help us understand the inter-individual variation in HbA1c.