Characteristics of the group
No differences regarding age or sex were observed between the groups. The healthy controls had higher education levels than did the patients with obesity. The two obesity subtypes did not differ in terms of obesity duration or BMI. (Table 1)
Table 1. Characteristics of the groups
Parameter
|
O+C
|
O-C
|
HC
|
Total, n (%)
|
78 (60,8)
|
21 (16,2)
|
30 (23,1)
|
Mean age, years (M ± SD)
|
43,33±10,49
|
38,4±8,51
|
44,5±8,55
|
Sex (female), n (%)
|
27 (34,6)
|
7 (33,3)
|
10 (33,3)
|
Education
|
|
|
|
primary, n (%)
|
1 (1,3)*&
|
0 (0)
|
0 (0)
|
vocational, n (%)
|
3 (3,84)*&
|
3 (14,3)&
|
0 (0)
|
secondary, n (%)
|
35 (44,88)*&
|
4 (19,0)&
|
0 (0)
|
higher education, n (%)
|
39 (50)&
|
14 (66,7)&
|
30 (100)
|
Prediabetes/diabetes,, n (%)
|
47 (60,3)
|
-
|
-
|
Hypertension, n (%)
|
36 (46,2)
|
-
|
-
|
Artherosclerosis, n (%)
|
34 (43,6)
|
-
|
-
|
Arthritis, n (%)
|
5 (6,4)
|
-
|
-
|
Psoriasis, n (%)
|
5(6,4)
|
-
|
-
|
PCOS, n (%)
|
2(2,6)
|
-
|
-
|
Nonalcoholic fatty liver disease, n (%)
|
3 (3,8)
|
-
|
-
|
Hypothyrosidism, n (%)
|
13 (16,7)
|
-
|
-
|
Graves-basedov disease, n (%)
|
3 (3,00)
|
-
|
-
|
Obstructive sleep apnea, n (%)
|
2(2,6)
|
-
|
-
|
Asthma, n (%)
|
5 (6,4)
|
-
|
-
|
COPD, n (%)
|
1 (1,3)
|
-
|
-
|
Duration of obesity, years (M ± SD)
|
20,31± 11,2
|
20,31± 10,02
|
-
|
BMI (kg/m2), (M ± SD)
|
44,98 ± 6,06&
|
44,34 ± 6,3&
|
23,06± 3,13
|
Muscle mass, kg (M ± SD)
|
65,45 ± 14,13&
|
64,83 ± 11,13&
|
50,88 ± 12,21
|
Percentage of body fat, % (M ± SD)
|
46,15 ± 6,83&
|
45,6± 7,24&
|
24,3 ± 7,97
|
Visceral fat index (n), M ± SD
|
19 ± 8&
|
18 ± 7&
|
5 ± 3
|
Basal metabolic rate (kcal)
|
2201 ± 328&
|
2179 ± 481&
|
1578 ± 362&
|
BMI, body mass index. *Significantly different from O-C, &Significantly different from HC; p<=0,05
|
The impact of obesity-related comorbidities on premature aging
Differences in chronological age, inflammatory markers (CRP, IL-6), telomere length, cognitive function (CTT-1 TEN, CTT-2 TEN, number of trials in Wisconsin Card Sorting Test) and metabolic age between a group of patients with obesity and comorbidity, obesity without comorbidity and healthy subjects were tested.
The Kruskal‒Wallis nonparametric test was used to assess the statistical significance of the differences presented. (Table 2), (Figure 1).
Table 2. The differences in chronological age markers between O+C, O-C and HC according to the Kruskal‒Wallis test.
|
Kruskal‒Wallis test parameters
|
pairwise comparisonsa
|
Chronological age
|
H(2)=5.88, p=0.053
|
HC vs O+C: p>0.999
HC vs O-C: p=0.057
O+C vs O-C: p=0.124
|
CRP
|
H(2)=68.11, p<0.001
|
HC vs O+C: p<0.001*
HC vs O-C: p<0.001*
O+C vs O-C: p>0.999
|
IL-6
|
H(2)=68.25, p<0.001
|
HC vs O+C: p<0.001*
HC vs O-C: p<0.001*
O+C vs O-C: p>0.999
|
Telomere length
|
H(2)=8.28, p=0.016
|
HC vs O+C: p=0.028*
HC vs O-C: p=0.043*
O+C vs O-C: p>0.999
|
CTT1-TEN
|
H(2)=1.08, p=0.584
|
HC vs O+C: p>0.999
HC vs O-C: p>0.999
O+C vs O-C: p>0.999
|
CTT2-TEN
|
H(2)=2.7, p=0.260
|
HC vs O+C: p=0.327
HC vs O-C: p>0.999
O+C vs O-C: p>0.999
|
Number of trials
|
H(2)=15.52, p<0.001
|
HC vs O+C: p=0.005*
HC vs O-C: p=0.001*
O+C vs O-C: p=0.369
|
Metabolic age
|
H(2)=42.05, p<0.001
|
HC vs O+C: p<0.001*
HC vs O-C: p=0.001*
O+C vs O-C: p=0.525
|
a - Adjusted with Bonferroni correction, CRP – C-reactive protein, CTT-1 TEN - TEN results from the Color Trails Test , CTT-2 TEN - TEN results from the Color Trails Test 2, HC – healthy controls, , IL-6 - interleukin-6, O+C - patients with obesity and comorbidities, O-C – patients without comorbidities, number of trials – number of tries in the Wisconsin Card Sorting Test, TL – telomere length, *p<0,05
|
Statistically significant differences in CRP levels were detected between the group with obesity and comorbidities (M=15.25, IQR=17.5) and the healthy group (M=0.5, IQR=0.3) (p<0.001) and between the group with obesity without comorbidities (M=15.6, IQR=10.1) and the healthy group (M=0.5, IQR=0.3) (p<0.001). Both groups with obesity had higher CRP levels than did the control group. Comorbidities did not affect CRP levels among patients with obesity (p>0.999).
Additionally, in terms of the IL-6 parameter, higher IL-6 levels were detected between the two groups of patients who were obese and the healthy group (M=3,62, IQR=2,9 vs M=1,15, IQR=0,23), (p<0,001) and (M=3,81, IQR=2,2 vs M=1,15, IQR=0,23), p<0,001), but no differences were detected between the subgroups of patients with obesity with and without comorbidities (p>0.999).
Telomere length
Patients with obesity had significantly shorter telomeres than did healthy individuals (M=3987, IQR=1456 vs M=4392, IQR=2510) (p=0,022). The same difference was observed between patients with obesity without comorbidities and healthy individuals (M=3851, IQR 1996 vs M=4392, IQR=2510) (p=0,043). No effect of comorbidities such as obesity on telomere length was observed. (p>0,0999).
Cognitive function
In terms of the CTT test, neither the CTT-1 (M=47, IQR=12 vs M=51, IQR=14 vs M=49, IQR=12) (p>0,05) nor the CTT-2 (M=51, IQR=19 vs M=56, IQR=23 vs M=55, IQR=9) showed statistically significant differences between any of the groups (p>0,999).
In terms of executive function, the Wisconsin Card Sorting Test showed a significantly worse outcome in patients with obesity with comorbidities than in healthy patients (M=127, IQR=42 vs M=87, IQR=42), (p=0.004) and patients with obesity without comorbidities than in healthy patients (M=128, IQR=17 vs M=87, IQR=42), p=0.001. Patients with obesity with or without comorbidities did not differ in the number of attempts to complete the test. (p=0.401)
Metabolic age
Both groups of patients with obesity and without obesity presented significantly greater metabolic age (M=57, IQR=13 vs M=38, IQR=20), (p<0,001), (M=52, IQR=17 vs M=38, IQR=20), (p=0,001), but comorbidities did not differ between subgroups of patients with obesity (p>0,999).
Effects of individual obesity-related diseases, namely, prediabetes/diabetes, hypertension, and atherogenic dyslipidemia, on biological age markers.
Linear regression was used to assess the potential relationships between BMI, comorbidities and inflammation, telomere length, cognitive function or metabolic age. The main components of metabolic syndrome (prediabetes/diabetes, hypertension, atherogenic dyslipidemia) were selected as comorbidities.
Seven models with inflammatory parameters (CRP or IL-6), telomere length, measures of cognitive function (CTT1-TEN, CTT2-TEN, the number of trials in the Wisconsin Card Sorting Test) and metabolic age as the dependent variables were built.
The detailed results of the regression model are described in the Online Supplementary Material.
The model for CRP, CTT-1 and metabolic age was statistically significant.
The presence of prediabetes, diabetes, hypertension or atherogenic dyslipidemia in obese individuals was not shown to significantly affect inflammatory parameters (CRP, IL-6). Only BMI had a significant effect on CRP levels.
The presence of prediabetes, diabetes, hypertension or dyslipidemia has not been shown to affect telomere length.
In terms of cognitive functioning, a significant effect of the presence of hypertension in obese individuals on the deterioration of the CTT-1 TEN score according to the color-linked test was observed. Other components of metabolic syndrome that cooccur with obesity were not shown to significantly affect the deterioration of cognitive function. However, the effect of CRP on the deterioration of cognitive function was observed.
Additionally, no significant correlation was found between components of metabolic syndrome and metabolic age in patients with obesity. The analysis revealed that the sole determinant influencing the metabolic age parameter was the chronological age of the subjects under study.