Bimodality in Blood Glucose Distribution: Is it universal?

Epidemiology/Health Services/Psychosocial Research

Bimodality in Blood Glucose Distribution

Diabetes Care 2002 Dec; 25(12): 2212-2217. https://doi.org/10.2337/diacare.25.12.2212

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Figure 1—
Histogram of log (post-challenge BG concentration) by ethnicity and age. Fitted bimodal normal curves are superimposed.

Table 1—

Characteristics of the sample by ethnic group and sex

	Malay	Chinese	Indian	Other Indigenous*	All
Men
n	4,282	2,446	638	1,483	8,849
Mean age† (years)	47 ± 13	48 ± 12	45 ± 12	46 ± 13	47 ± 13
Mean BMI†	23.3 ± 3.9	23.6 ± 3.7	23.9 ± 3.6	22.6 ± 3.7	23.8 ± 3.8
% BMI
<25 kg/m²	71	67	67	76	70
25–29.9 kg/m²	24	28	28	21	25
≥30 kg/m²	5	5	5	3	5
Mean BG†	5.5 ± 3.5	6.0 ± 3.6	7.0 ± 4.8	4.9 ± 2.3	5.7 ± 3.5
Prevalence of impaired glucose tolerance‡ (%)	3.5 ± 0.3	5.7 ± 0.5	6.7 ± 1.0	2.7 ± 0.5	4.4 ± 0.2
Prevalence of diabetes‡ (%)	6.0 ± 0.4	7.3 ± 0.6	16.3 ± 1.5	2.7 ± 0.5	7.0 ± 0.3
Age-standardized prevalence of diabetes‡§ (%)	6.5 ± 0.5	7.1 ± 0.6	19.5 ± 2.0	2.9 ± 0.6	—
Women
n	4,992	2,929	743	1,705	10,369
Mean age† (years)	46 ± 13	47 ± 13	45 ± 12	45 ± 13	46 ± 13
Mean BMI†	24.2 ± 4.7	23.4 ± 4.1	24.7 ± 4.9	23.1 ± 4.4	23.8 ± 4.5
% BMI
<25 kg/m²	62	72	60	71	66
25–29.9 kg/m²	26	22	28	22	25
>30 kg/m²	11	6	12	7	9
Mean BG†	5.8 ± 3.5	6.1 ± 3.4	6.6 ± 4.3	5.4 ± 3.0	5.9 ± 3.5
Prevalence of impaired glucose tolerance‡ (%)	4.3 ± 0.3	6.3 ± 0.5	6.1 ± 1.0	3.4 ± 0.5	5.0 ± 0.3
Prevalence of diabetes‡ (%)	6.6 ± 0.4	8.0 ± 0.5	11.5 ± 1.2	4.2 ± 0.6	7.1 ± 0.2
Age-standardized prevalence of diabetes‡§ (%)	7.5 ± 0.5	7.8 ± 0.6	11.6 ± 1.4	4.8 ± 0.7	—

*
↵* Other Indigenous refers to indigenous people of Sabah and Sarawak on the island of Borneo;
†
↵† means ± SD;
‡
↵‡ means ± SE;
§
↵§ age-standardized to Segi’s world population.

Table 2—

Parameter estimates of unimodal and bimodal models for post-challenge BG distributions in four ethnic populations

Ethnic/age group	n	% With diabetes	Unimodal normal model					Bimodal normal model
						Mean	Geometric mean (mmol/l)	SD	First mode					Second mode
						Mean	Geometric mean (mmol/l)	SD				Mean	Geometric mean (mmol/l)	SD	Mean	Geometric mean (mmol/l)	SD	% in second mode	Cut point
Malay (age in years)
30–39	3,426	1.7	1.5	4.7	0.3	1.5	4.6	0.3	2.8	16.1	0.3	1.6	11.5
40–49	2,575	3.3	1.6	4.9	0.4	1.5	4.7	0.3	2.7	15.2	0.3	3.6	10.9
50–59	1,480	3.7	1.6	5.0	0.4	1.6	4.8	0.3	2.7	14.9	0.3	3.9	11.1
≥60	427	3.7	1.6	5.2	0.4	1.6	5.0	0.3	2.8	16.6	0.3	3.4	12.2
Chinese (age in years)
30–39	1,718	1.3	1.6	4.8	0.3	1.6	4.8	0.3	2.6	13.8	0.3	1.3	11.6
40–49	1,549	2.1	1.6	5.1	0.3	1.6	5.0	0.3	2.6	13.4	0.3	2.1	11.6
50–59	973	3.4	1.7	5.3	0.4	1.6	5.1	0.3	2.7	15.2	0.3	2.6	12.5
≥60	862	6.2	1.7	5.7	0.4	1.7	5.3	0.3	2.8	16.0	0.3	5.5	12.3
Indian (age in years)
30–39	576	3.0	1.6	5.0	0.4	1.6	4.8	0.3	2.7	14.8	0.3	3.4	11.0
40–49	356	5.1	1.7	5.3	0.4	1.6	5.0	0.3	2.8	17.1	0.2	4.1	12.9
50–59	145	4.8	1.7	5.7	0.4	1.7	5.4	0.3	2.9	17.6	0.3	3.8	13.3
≥60	166	5.4	1.7	5.2	0.4	1.6	5.0	0.4	2.7	15.5	0.4	4.9	12.1
Other Indigenous (age in years)
30–39	1,386	0.9	1.5	4.5	0.3	1.5	4.5	0.3	2.7	15.4	0.3	0.8	11.8
40–49	768	2.5	1.6	4.8	0.4	1.5	4.6	0.3	3.0	19.3	0.3	1.6	13.1
50–59	465	3.0	1.6	4.8	0.4	1.5	4.6	0.3	2.8	16.3	0.3	2.8	11.6
≥60	525	3.8	1.6	5.0	0.4	1.6	4.8	0.3	2.7	15.0	0.3	3.3	11.9

Table 3—

Parameter estimates of unimodal and bimodal models for post-challenge BG distributions in four ethnic populations

Ethnic/age group	n	% With diabetes	Unimodal normal model					Bimodal normal model
						Mean	Geometric mean (mmol/l)	SD	First mode					Second mode
						Mean	Geometric mean (mmol/l)	SD				Mean	Geometric mean (mmol/L)	SD	Mean	Geometric mean (mmol/l)	SD	% in second mode	Cut point
Malay (age in years)
30–39	3,461	2.7	1.6	4.8	0.4	1.5	4.6	0.3	2.8	15.8	0.3	2.7	11.0
40–49	2,667	6.7	1.6	5.1	0.4	1.5	4.7	0.3	2.7	15.0	0.3	7.4	10.3
50–59	1,587	10.1	1.7	5.4	0.5	1.6	4.7	0.3	2.7	15.3	0.3	11.0	10.2
≥60	1,559	11.9	1.7	5.7	0.5	1.6	4.9	0.3	2.7	15.6	0.3	12.6	10.5
Chinese (age in years)
30–39	1,725	1.7	1.6	4.8	0.3	1.6	4.8	0.3	2.6	13.8	0.3	1.7	11.3
40–49	1,608	5.7	1.7	5.3	0.4	1.6	5.0	0.3	2.7	14.9	0.3	6.0	10.8
50–59	1,048	10.3	1.7	5.7	0.5	1.6	5.1	0.3	2.7	14.8	0.3	10.8	10.6
≥60	994	18.6	1.9	6.5	0.5	1.7	5.3	0.3	2.8	15.7	0.3	18.0	11.8
Indian (age in years)
30–39	590	5.3	1.6	5.1	0.4	1.6	4.8	0.3	2.6	13.8	0.3	6.0	10.3
40–49	396	14.7	1.8	5.9	0.5	1.6	5.0	0.3	2.8	16.4	0.2	14.0	11.2
50–59	182	24.2	2.0	7.1	0.6	1.7	5.4	0.3	2.8	16.9	0.3	25.0	10.6
≥60	213	26.3	1.9	6.7	0.6	1.6	4.9	0.3	2.7	15.0	0.3	28.1	9.4
Other Indigenous (age in years)
30–39	1,392	1.3	1.5	4.6	0.3	1.5	4.5	0.3	2.7	15.0	0.3	1.3	11.3
40–49	780	4.0	1.6	4.8	0.4	1.5	4.6	0.3	2.8	16.5	0.3	3.7	11.5
50–59	472	4.5	1.6	4.9	0.4	1.5	4.6	0.3	2.8	16.4	0.3	4.3	11.4
≥60	544	7.2	1.7	5.2	0.4	1.6	4.8	0.3	2.7	14.5	0.3	6.9	10.9