Genotype and allele frequencies of MC4R rs17782313 SNP among 282 Iranian women participated in this study are reported in Table 1. The prevalence of the T allele was 54.04%, while C allele was 45.96%. Participants were categorized based on MC4R rs17782313 genotypes and divided into two groups: TT genotype (n = 153) and TC + CC genotype (n = 129) (Table 2). All participants were generally (BMI ˃25 kg/m2) and centrally (WC ˃ 80 cm) obese. The mean BMI, WC, BMR, and BMR/kg of the TT genotype carriers were 31.06±4.66 kg/m2, 99.16±10.31 cm, 1391.22±119.50 kcal/day, and 17.35±1.74, respectively, while corresponding values for TC+CC carriers were 30.78±3.90 66 kg/m2, 98.53±9.81 cm, 1368.69±120.51 kcal/day, and 17.29±1.50, respectively, with no significant difference between two groups. There were no significant difference between genotypes in terms of demography, anthropometry, body composition, and blood parameters, as well as physical activity, marital status, smoking status, and education level. After adjustment for covariates including age and physical activity, a significant difference in height (p=0.04) was observed between two groups (Table 2). After adjustment for calorie intake, no significant difference in food intake was revealed between the MC4R rs17782313 genotypes (Table 3).
Comparing women who consumed a diet with GI, GL, or carbohydrate less than the median with women who consumed higher than the median, there were no differences in BMI, WC, and BMR (p > 0.05), but women with higher carbohydrate intake, compared with those with lower intake, had a height BMR/kg (low intake: 17.16±1.53 vs. high intake: 17.41±1.74; p= 0.01). After adjustment for age and energy intake, significant interactions were observed between dietary carbohydrate intake and MC4R rs17782313 in terms of BMI (P Interaction = 0.007), WC (P Interaction = 0.02), and RMR/kg (P Interaction = 0.003) in this way that higher carbohydrate intake, compared with lower intake, was associated with an increase in BMI and WC for individuals with C allele carriers (TC + CC genotypes), while related to an increase in BMR/kg for those carrying the TT genotype (Fig. 1). No significant interaction was found between MC4R rs17782313 and GI (Fig. 2) and GL (Fig. 3) on BMI, WC, BMR/kg, and BMR
Table 1 MC4R rs17782313 genotypes and allelic variants of study population
|
Alleles frequency
|
|
Genotypes frequency
|
|
T
|
C
|
|
|
TT
|
TC
|
CC
|
|
|
N=307
(54.04%)
|
N=261
(45.96%)
|
N=120
(42.3%)
|
N=67
(23.6%)
|
N=97
(34.1%)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Table 2. Characteristics of the study participants according to MC4R rs17782313 genotypes
|
Total
|
MC4R rs17782313 genotypes
|
|
N= 282
|
TT
(n=153)
|
TC +CC (n=129)
|
p-value
|
p-value*
|
Demography and anthropometry
|
|
|
|
Age (year)
|
|
37.23±8.65
|
35.77±8.03
|
0.14
|
0.10
|
Height (cm)
|
|
161.90±5.85
|
160.98±5.81
|
0.19
|
0.04a
|
Weight (kg)
|
|
81.06±12.32
|
80.28±12.48
|
0.60
|
0.91a
|
BMI (kg/m2)
|
|
31.06±4.66
|
30.78±3.90
|
0.58
|
0.46a
|
WC (cm)
|
|
99.16±10.31
|
98.53±9.81
|
0.60
|
0.67a
|
WHR
|
|
0.93 ±0.05
|
1.64 ±8.00
|
0.27
|
0.49a
|
Body composition
|
|
|
|
|
|
Fat percentage (%)
|
|
41.38±5.56
|
41.40±5.39
|
0.97
|
0.32a
|
Fat mass (kg)
|
|
34.02±8.99
|
33.68±8.30
|
0.74
|
0.42a
|
FFM (%)
|
|
47.27±5.53
|
46.23±5.57
|
0.11
|
0.16a
|
Visceral fat (%)
|
|
16.42±11.41
|
16.93±17.32
|
0.76
|
0.63a
|
TBW (%)
|
|
34.72±4.06
|
33.98±4.10
|
0.73
|
0.19a
|
Trunk fat (%)
|
|
16.55±3.77
|
16.47±3.64
|
0.85
|
0.36a
|
BMR (kcal/day)
|
|
1391.22±119.50
|
1368.69±120.51
|
0.11
|
0.16a
|
BMR/KG
|
|
17.35±1.74
|
17.29±1.50
|
0.77
|
0.17a
|
Blood parameters
|
|
|
|
|
|
FBS (mg/dL)
|
|
87.94±10.21
|
86.24±8.46
|
0.16
|
0.46
|
TC (mg/dL)
|
|
185.19±34.12
|
184.83±38.08
|
0.93
|
0.33
|
TG (mg/dL)
|
|
127.89±74.23
|
114.52±64.32
|
0.13
|
0.31
|
HDL-C (mg/dL)
|
|
46.35±9.94
|
47.07±11.98
|
0.60
|
0.37
|
LDL-C (mg/dL)
|
|
95.81±23.23
|
93.84±25.24
|
0.52
|
0.95
|
hs-CRP (mg/L)
|
|
4.27±4.53
|
4.62±4.85
|
0.56
|
0.17
|
Blood pressure
|
|
|
|
|
|
SBP (mmHg)
|
|
112.16±14.04
|
110.92±13.78
|
0.46
|
0.28
|
DBP (mmHg)
|
|
77.92±9.59
|
77.49±9.87
|
0.71
|
0.50
|
Physical activity score
|
|
1238.64±1892.47
|
1177.10±2371.62
|
0.82
|
0.92
|
Smoking
|
|
|
|
0.24
|
0.20
|
yes
|
15
|
6
|
9
|
|
|
no
|
267
|
148
|
119
|
|
|
Marital status
|
|
|
|
0.92
|
0.73
|
Married
|
219
|
120
|
99
|
|
|
Single
|
54
|
29
|
25
|
|
|
Divorced
|
8
|
5
|
3
|
|
|
Education level
|
|
|
|
0.11
|
0.10
|
Illiterate
|
3
|
0
|
3
|
|
|
≤Diploma
|
119
|
63
|
56
|
|
|
University degree
|
160
|
91
|
69
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Categorical variables are presented as frequency (n), and continuous variables as mean ± SD.
BMI, body mass index; WC, waist circumference; WHR, waist-to-hip ratio; FBS, fasting blood sugar; FFM, fat free mass; HDL-C, high density lipoprotein cholesterol; hs-CRP, high-sensitivity C reactive protein; LDL-C, low density lipoprotein cholesterol; BMR, basal metabolic rate; TBW, Total body water; TG, triacylglycerol; TC, total cholesterol; SBP, systolic blood pressure; DBP, diastolic blood pressure.
* After adjustment for age, BMI and physical activity
a BMI considered as collinear and these variables were adjusted for age and physical activity
Table 3 Dietary intake of study population according to MC4R rs17782313 genotypes
|
Total
|
MC4R rs17782313 genotypes
|
|
N= 282
|
TT
(n=153)
|
TC +CC (n=129)
|
p-value
|
p-value*
|
Macronutrient
|
|
|
|
|
|
Energy (kcal)
|
|
2614.27±753.50
|
2588.40±709.46
|
0.77
|
-
|
Carbohydrate (g)
|
|
372.68±123.59
|
367.74±111.35
|
0.73
|
0.84
|
Protein (g)
|
|
89.61±27.72
|
86.76±29.01
|
0.40
|
0.32
|
Fat (g) )
|
|
93.65±31.92
|
96.04±33.63
|
0.92
|
0.59
|
Fatty acids
|
|
|
|
|
|
Saturated (g)
|
|
28.21±11.57
|
27.34±9.90
|
0.51
|
0.52
|
Polyunsaturated (g)
|
|
19.48 ±8.66
|
20.41±9.59
|
0.39
|
0.24
|
Monounsaturated (g)
|
|
30.89±11.17
|
31.37±12.38
|
0.73
|
0.48
|
Linoleic (g)
|
|
16.77±8.22
|
17.67±9.06
|
0.38
|
0.26
|
Linolenic (g)
|
|
1.21±0.66
|
1.25±0.70
|
0.56
|
0.41
|
Oleic (g)
|
|
27.67±10.70
|
28.21±11.84
|
0.69
|
0.47
|
Trans (g)
|
|
0.009±0.002
|
0.009±0.002
|
0.85
|
0.86
|
Minerals
|
|
|
|
|
|
Selenium (mg)
|
|
122.61±45.65
|
115.40±38.36
|
0.16
|
0.08
|
Calcium (mg)
|
|
1180.02±421.32
|
1126.84±394.45
|
0.28
|
0.23
|
Phosphorus (mg)
|
|
1657.13±520.98
|
1594.45±495.01
|
0.31
|
0.18
|
Magnesium (mg)
|
|
467.57±153.76
|
443.32±135.56
|
0.17
|
0.06
|
Zinc (mg)
|
|
13.00±4.13
|
12.67±4.11
|
0.51
|
0.45
|
Iron (mg)
|
|
18.67±5.92
|
18.38±5.84
|
0.67
|
0.74
|
Copper (mg)
|
|
1.98±0.65
|
1.97±0.77
|
0.90
|
0.86
|
Vitamins
|
|
|
|
|
|
E (mg)
|
|
16.92±8.51
|
17.44±9.63
|
0.63
|
0.54
|
D (μg)
|
|
1.94±1.67
|
1.94±1.47
|
0.99
|
0.91
|
A (RAE)
|
|
802.96±438.62
|
734.13±351.96
|
0.15
|
0.15
|
K (μg)
|
|
229.11±212.74
|
197.71±170.86
|
0.18
|
0.19
|
B1 (mg)
|
|
2.10±0.67
|
2.03±0.62
|
0.33
|
0.18
|
B2 (mg)
|
|
2.19±0.75
|
2.16±0.84
|
0.72
|
0.83
|
B3 (mg)
|
|
25.30±8.42
|
25.02±10.06
|
0.80
|
0.96
|
B5 (mg)
|
|
6.51±2.10
|
6.42±2.73
|
0.76
|
0.88
|
B6 (mg)
|
|
2.20±0.69
|
2.12±0.72
|
0.33
|
0.23
|
B9 (μg)
|
|
614.13±179.57
|
591.83±169.77
|
0.73
|
0.17
|
B12 (μg)
|
|
4.31±2.21
|
4.30±2.25
|
0.97
|
0.90
|
C (mg)
|
|
196.48±114.00
|
190.16±138.70
|
0.67
|
0.75
|
Others
|
|
|
|
|
|
Caffeine (mg)
|
|
159.39±184.84
|
138.71±98.94
|
0.26
|
0.28
|
Fiber (g)
|
|
45.07±19.28
|
44.31±17.59
|
0.73
|
0.84
|
*After adjustment for calories intake