Handgrip strength improves prediction of type 2 diabetes: a prospective cohort study

Figures & data

Table 1. Baseline participant characteristics, overall and by incident T2D status.

	Overall (N = 776) Mean (SD), median (IQR) or n (%)	Developed T2D (N = 59) Mean (SD), median (IQR) or n (%)	No T2D (N = 717) Mean (SD), median (IQR) or n (%)	p-value
Normalized handgrip strength (kPa/kg^2/3)	0.49 (0.23)	0.39 (0.13)	0.49 (0.24)	.001
Questionnaire/Prevalent conditions
Age at survey (years)	69 (3)	69 (3)	69 (3)	.86
Males	366 (47.2)	24 (40.7)	342 (47.7)	.30
Family history of diabetes	258 (33.3)	21 (35.6)	237 (33.1)	.69
Current smokers	74 (9.5)	6 (10.2)	68 (9.5)	.98
History of hypertension	347 (44.7)	27 (45.8)	320 (44.6)	.87
Physical measurements
Weight (kg)	75.2 (12.9)	81.9 (12.5)	74.7 (12.8)	<.001
Height (cm)	164 (9)	163 (8)	164 (9)	.38
BMI (kg/m^2)	27.9 (4.3)	30.8 (5.1)	27.6 (4.2)	<.001
Waist circumference (cm)	92.4 (11.7)	98.3 (11.3)	92.0 (11.6)	<.001
SBP (mmHg)	139 (18)	140 (21)	138 (17)	.52
DBP (mmHg)	80 (9)	82 (11)	80 (9)	.12
Energy expenditure of total LTPA (kcal/day)	386 (232–680)	407 (258–702)	382 (231–677)	.93
Blood-based markers
Total cholesterol (mmol/L)	5.48 (0.93)	5.31 (0.91)	5.50 (0.93)	.14
HDL-C (mmol/L)	1.25 (0.31)	1.19 (0.27)	1.25 (0.31)	.11
FPG (mmol/L)	4.90 (0.52)	5.45 (0.58)	4.86 (0.48)	<.001

BMI: body mass index; DBP: diastolic blood pressure; FPG: fasting plasma glucose; HDL-C: high-density lipoprotein cholesterol; IQR: interquartile range; LTPA: leisure-time physical activity; SD: standard deviation; SBP: systolic blood pressure; T2D: type 2 diabetes.

Table 2. Overall and sex-specific association of normalized handgrip strength with type 2 diabetes.

	Overall (776 participants, 59 cases)		Men (366 participants, 24 cases)		Women (410 participants, 35 cases)		p-value for interaction
Models	HR (95% CI)	p-value	HR (95% CI)	p-value	HR (95% CI)	p-value
Model 1	0.38 (0.24–0.57)	<.001	0.66 (0.32–1.37)	.26	0.29 (0.17–0.49)	<.001	.08
Model 2	0.49 (0.31–0.80)	.004	1.04 (0.45–2.42)	.92	0.37 (0.21–0.67)	.001	.04
Model 3	0.54 (0.31–0.95)	.03	0.57 (0.22–1.46)	.24	0.56 (0.28–1.13)	.10	N/A
Model 4	0.53 (0.29–0.97)	.04	1.07 (0.43–2.67)	.89	0.41 (0.20–0.81)	.01	.06

CI: confidence interval; HR: hazard ratio; HRs are reported per standard deviation increase. Model 1: Adjusted for age and sex (not adjusted for sex in the sex-specific analysis). Model 2: Model 1 plus high-density lipoprotein cholesterol, systolic blood pressure, smoking status, physical activity, family history of diabetes and fasting plasma glucose. Model 3: Sex, smoking, parental history of diabetes, hypertension and waist circumference (adjusted for smoking, hypertension and waist circumference in men and parental history of diabetes, hypertension and waist circumference in women). Model 4: Age, sex, waist circumference, smoking, parental diabetes, hypertension and glucose (not adjusted for sex in the sex-specific analyses).

Table 3. Risk discrimination and reclassification upon addition of normalized handgrip strength to the DESIR T2D risk prediction model containing conventional risk factors.

Discrimination	Overall	Men	Women
C-index (95% CI): conventional risk factors	0.6596 (0.5904 to0.7288)	0.5508 (0.4303 to 0.6713)	0.7441 (0.6697 to 0.8185)
C-index (95% CI): conventional risk factors plus HGS	0.6979 (0.6261 to 0.7698)	0.6326 (0.5284 to 0.7368)	0.7588 (0.6804 to 0.8371)
C-index change (95% CI)	0.0383 (–0.0047 to 0.0814)	0.08181 (–0.0429 to 0.2065)	0.0147 (–0.0167 to 0.0460)
p-value	.08	.20	.36
p-value for difference in −2 log likelihood	.01	.25	.03
Reclassification
Continuous Net reclassification index (95% CI)	33.26% (–18.09 to 84.60)	55.20% (–44.08 to 154.49)	15.09% (–49.11 to 79.29)
p-value	.20	.28	.65
Integrated discrimination index (95% CI)	0.0122 (0.0002 to 0.0242)	0.0075 (–0.008 to 0.0178)	0.0160 (–0.0001 to 0.0321)
p-value	.05	.16	.05

DESIR: Data from the Epidemiological Study on the Insulin Resistance Syndrome; HGS: handgrip strength; T2D: type 2 diabetes. The model with conventional risk factors included sex, smoking, parental history of diabetes, hypertension and waist circumference (smoking, hypertension and waist circumference for men and parental history of diabetes, hypertension and waist circumference for women).

Table 4. Risk discrimination and reclassification upon addition of normalized handgrip strength to the KORA S4/F4T2D risk prediction model containing conventional risk factors.

Discrimination	Overall	Men	Women
C-index (95% CI): conventional risk factors	0.8052 (0.7462 to 0.8642)	0.7255 (0.6146 to 0.8365)	0.8634 (0.8060 to 0.9207)
C-index (95% CI): conventional risk factors plus HGS	0.8234 (0.7646 to 0.8821)	0.7780 (0.6791 to 0.8770)	0.8758 (0.8206 to 0.9310)
C-index change (95% CI)	0.0182 (–0.0079 to 0.0443)	0.0525 (–0.0059 to 0.1108)	0.0124 (–0.0046 to 0.0295)
p-value	.17	.08	.15
p-value for difference in −2 log likelihood	.01	.33	.04
Reclassification
Continuous Net reclassification index (95% CI)	58.44% (35.16 to 81.72)	55.58% (–41.47 to 152.64)	59.90% (28.18 to 91.63)
p-value	<.001	.26	<.001
Integrated discrimination index (95% CI)	0.1965 (0.1403 to 0.2527)	0.0125 (–0.0024 to 0.0275)	0.3236 (0.2350 to 0.4122)
p-value	<.001	.10	<.001

KORA: Cooperative Health Research in the Region of Augsburg; HGS: handgrip strength; T2D, type 2 diabetes. The model with conventional risk factors included age, sex, waist circumference, parental history of diabetes, smoking and hypertension (sex was not included in the separate models for men and women).