Association Between Dietary Habits and Type 2 Diabetes Mellitus in Thai Adults: A Case-Control Study

Figures & data

Table 1 Inclusion and Exclusion Criteria for Study Participants

	Case	Control
Inclusion	25–74 years old; either sex	25–74 years old; either sex
	Residents of Chiang Mai province	Residents of Chiang Mai province
	All races and religions	All races and religions
	Diagnosed as T2DM within 6 months before data collection	Residents who are not diabetes (excluded based on blood glucose screening test)
	Diagnosed according to fasting plasma glucose level ≥126 mg/dL (7.0mmol/L) or two hours OGTT level ≥200 mg/dL (11.1 mmol/L)
Exclusion	Non-residents of Chiang Mai, neither foreigners nor tourists	Non-residents of Chiang Mai, neither foreigners nor tourists
	Who is not able to undertake an interview and measurements personally and/or not willing to participate	Who is not able to undertake an interview and measurements personally and/or not willing to participate
	In a long-term modification of diet	Those diagnosed with chronic diseases like kidney failure

Abbreviation: OGTT, Oral Glucose Tolerance Test.

Table 2 Socio-Demographic Characteristics of the Participants

	Control (n= 150) n (%)	Case (n= 150) n (%)	Value χ^2	p-value
Sex			7.1	0.008**
Male	41 (27.3)	63 (42.0)
Female	109 (72.7)	87 (58.0)
Age			1.9	0.165
Under 60 years	85 (56.7)	73 (48.7)
60 years and older	65 (43.3)	77 (51.3)
Level of education			1.3	0.262
No formal schooling	19 (12.7)	13 (8.7)
Primary, Secondary, or High school completed	131 (87.3)	137 (91.3)
Marriage status			0.8	0.676
Single	13 (8.7)	16 (10.6)
Divorce	30 (20.0)	25 (16.7)
Currently married	107 (71.3)	109 (72.7)
Work status over the past 12 months			2.6	0.109
Employed	95 (63.3)	108 (72.0)
Unemployed	55 (36.7)	42 (28.0)
Average household monthly income (Baht/monthly)^a			12.7	<0.001***
<12,842	108 (72.0)	78 (52.0)
≥12,842	42 (28.0)	71 (48.0)
BMI			0.6	0.751
<22	39 (26.0)	42 (28.0)
22–25	49 (32.7)	43 (28.7)
>25	62 (41.3)	65 (43.3)
High Waist Circumference			1.2	0.282
No	60 (40.3)	51 (34.0)
Yes	89 (59.7)	99 (66.0)

Notes: Chi-square test was used to compare categorical variables; %: ratio of valid responses; p-value for the comparison between two groups: ***p<0.001, **p<0.01. All p-values are two-sided. ^aThe mean of valid responses was used as a cut-off point for average monthly household income. There is 1 missing value for the average household monthly income. High Waist Circumference is defined as a waist ≥ 90 cm for males and a waist ≥ 80 cm for females. 1 missing data in the control group for high waist circumference.

Table 3 Lifestyle-Related Behaviors of the Participants

	Control (n=150) n (%)	Case (n=150) n (%)	Value χ^2	p-value
Family history of diabetes			19.0	<0.001***
No	128 (85.3)	95 (63.3)
Yes	22 (14.7)	55 (36.7)
Medication for T2DM			292.1	<0.001***
No	150 (100)	2 (1.3)
Yes	0	148 (98.7)
Hypertension			103.4	<0.001***
No	122 (81.3)	34 (22.7)
Yes	28 (18.6)	116 (77.3)
Physical activity knowledge			26.0	0.001**
No	31 (20.7)	3 (2.0)
Yes	119 (79.3)	147 (98.0)
Alcohol consumption			32.3	0.001**
Never	58 (38.7)	105 (70.0)
Quit	34 (22.7)	10 (6.7)
Regularly drinking	58 (38.7)	35 (23.3)
Smoking			0.5	0.775
Never	110 (73.3)	112 (74.7)
Ex-smoker	23 (15.3)	19 (12.7)
Current smoker	17 (11.3)	19 (12.7)

Notes: Chi-square test was used to compare categorical variables; %: ratio of valid responses; p-value for the comparison between two groups: ***p<0.001, **p<0.01. All p-values are two-sided. Those who had taken medicine to treat raised blood pressure during the past two weeks were categorized as hypertensive.

Table 4 Comparison of Food Intake by High-Frequency Analysis Between Diabetes and Non-Diabetes Participants

	Control (n=150) n (%)	Case (n=150) n (%)	Value χ^2	p-value
Rice	149 (99.3)	100 (66.7)	56.7	<0.001***
Bread	7 (4.7)	6 (4.0)	0.1	0.777
Noodles	2 (1.3)	0	2.0	0.156
Meat	39 (26.0)	46 (30.7)	0.8	0.370
Fish	9 (6.0)	6 (4.0)	0.6	0.427
Egg	28 (18.7)	15 (10.0)	4.6	0.032*
Beans	0	2 (1.3)	2.0	0.157
Nuts	0	1 (0.7)	1.0	0.317
Diary milk product	15 (10.0)	9 (6.0)	0.2	0.202
Non-dairy milk product	8 (5.3)	6 (4.0)	0.3	0.593
Deep fried food	48 (32.0)	1 (0.7)	54.3	<0.001***
Stir-fried food	55 (36.7)	4 (2.7)	54.9	<0.001***
Vegetables (every day)	104 (69.3)	71 (47.3)	14.9	<0.001***
Vegetables ≥ 3 servings/a day	27 (20.5)	105 (79.5)	82.3	<0.001***
Fruits (every day)	57 (38.0)	35 (23.3)	7.6	0.006**
Fruits ≥ 3 servings/a day	24 (16.0)	58 (38.7)	19.4	<0.001***
Seasonings	54 (36.0)	85 (56.7)	12.9	<0.001***
Fermented food and pickles	15 (10.0)	11 (7.3)	0.7	0.412
Dessert	4 (2.7)	3 (2.0)	0.1	0.702
Soft drinks	16 (10.7)	21 (14.0)	0.8	0.380
Coffee and/or tea	69 (46.0)	32 (21.3)	20.4	<0.001***
Fresh fruit juice everyday	2 (1.3)	0	2.0	0.156
Taking Supplements	4 (2.7)	8 (5.3)	1.4	0.239

Notes: Chi-square test was utilized to compare categorical variables; High frequency: eating every day, %: ratio of valid responses; p-value for the comparison between two groups: ***p<0.001, **p<0.01, *p<0.05. All p-values are two-sided. Beans 1 missing data, Deep fried food 1 missing data.

Table 5 Comparison of Dietary Behaviours by High Frequency Between Diabetes and Non-Diabetes Participants

	Control (n=150) n (%)	Case (n=150) n (%)	Value χ^2	p-value
Three meals a day	136 (90.7)	128 (85.3)	2.0	0.155
Breakfast skipping	62 (41.3)	32 (21.3)	13.9	<0.001***
Having meals with family	99 (66.0)	106 (70.7)	0.5	0.482
Cooking by yourself	109 (72.7)	108 (72.0)	0.0	0.897
Not removing visible fat	93 (62.0)	134 (89.3)	30.4	<0.001***
Eating out	12 (8.0)	12 (8.0)	0.0	0.986
Snacking between meals	4 (2.7)	8 (5.3)	1.4	0.239

Notes: Chi-square test was utilized to compare categorical variables; High frequency: eating every day, %: ratio of valid responses; p-value for the comparison between two groups: ***p<0.001. All p-values are two-sided. Eating out 3 missing data (2 control 1 case), Having meals with family 2 missing data (control group).

Table 6 Knowledge Related to Nutrition

Have You Received Knowledge Related to Nutrition?	Control (n=150) n (%)	Case (n=150) n (%)	Value χ^2	P-value
Yes	110 (73.3)	143 (95.3)	27.5	<0.001***
No	40 (26.7)	7 (4.7)

Notes: Chi-square test was used to compare categorical variables; %: ratio of valid responses; p-value for the comparison between two groups: ***p<0.001.

Figure 1 The sources of nutrition knowledge received by participants.

Note: Sources are not mutually exclusive.

Table 7 Factors Associated with Diabetes Through Logistic Regression Analysis

Variable	Total n=300	Control n=150	Case n=150	Univariate Analysis		Multivariable Analysis
		n (%)	n (%)	OR (95% CI)	p-value	OR (95% CI)	p-value
Breakfast skipping	94	62 (41.3)	32 (21.3)	0.40 (0.22–0.66)	<0.001	0.41 (0.24–0.69)	0.001
Not removing visible fat	227	93 (62.0)	134 (89.3)	5.13 (2.78–9.49)	<0.001	5.17 (2.76–9.70)	<0.001
Rice every day	249	149 (99.3)	100 (66.7)	0.01 (0.00–0.08)	<0.001	0.01 (0.00–0.09)	<0.001
Egg every day	43	28 (18.7)	15 (10.0)	0.48 (0.23–0.99)	0.032	0.50 (0.25–0.99)	0.048
Deep fried food	49	48 (32.0)	1 (0.7)	0.01 (0.00–0.08)	<0.001	0.01 (0.00–0.09)	<0.001
Stir-fried food	59	55 (36.7)	4 (2.7)	0.05 (0.01–0.13)	<0.001	0.05 (0.02–0.13)	<0.001
Vegetable every day	175	104 (69.3)	71 (47.3)	0.40 (0.24–0.65)	<0.001	0.42 (0.26–0.67)	<0.001
Vegetables ≥ 3 servings/a day	132	27 (18.0)	105 (70.0)	10.60 (6.17–18.3)	<0.001	10.53 (6.06–18.3)	<0.001
Fruit every day	92	57 (38.0)	35 (23.3)	0.50 (0.29–0.84)	0.006	0.56 (0.33–0.95)	0.031
Fruits ≥ 3 servings/a day	82	24 (16.0)	58 (38.7)	3.31 (1.86–5.98)	<0.001	3.29 (1.88–5.72)	<0.001
Seasonings	139	54 (36.0)	85 (56.7)	2.32 (1.46–3.70)	<0.001	2.25 (1.40–3.61)	0.001
Coffee and/or tea	101	69 (46.0)	32 (21.3)	0.32 (0.18–0.54)	<0.001	0.33 (0.19–0.56)	<0.001

Notes: Controlled by adjusting for Age, Sex, and BMI.

Table 8 Dietary Habits Associated with T2DM Among the Adult Residents of Chiang Mai, Thailand

Association of Dietary Habits to T2DM
Dietary Behaviour/ Food Type	OR	aOR	95% CI	p-value
Not Removing visible fat
Crude	5.13		2.69–10.10	<0.001***
Model 1		5.18	2.76–9.70	<0.001***
Model 2		5.35	2.36–12.10	<0.001***
Model 3		5.61	2.29–13.70	<0.001***
Vegetables every day
Crude	0.40		0.24–0.65	<0.001***
Model 1		0.42	0.26–0.67	<0.001***
Model 2		0.31	0.16–0.62	0.001**
Model 3		0.32	0.15–0.68	0.003**
Fruits every day
Crude	0.50		0.29–0.84	0.006**
Model 1		0.56	0.33–0.95	0.030*
Model 2		0.70	0.35–1.41	0.320
Model 3		0.95	0.43–2.11	0.910
Seasonings
Crude	2.32		1.42–3.79	<0.001***
Model 1		2.25	1.40–3.61	0.001**
Model 2		2.19	1.15–4.16	0.017*
Model 3		3.52	1.69–7.32	0.001**

Notes: Multiple Logistic Regression Analysis; Crude: unadjusted; p-value: ***p<0.001, **p<0.01, *p<0.05. Model 1: adjusted for age, sex. Model 2: Model 1 + BMI, Occupation status, Household monthly income level, Hypertension, Family history of diabetes, Alcohol consumption. Model 3: Model 1 + Model 2+ not removing visible fat/ vegetables/ fruits/ seasonings.

Abbreviations: OR, odds ratio; aOR, adjusted odds ratio; CI, confidence interval.