Sex differences in the association between the muscle quality index and the incidence of depression: A cross-sectional study

Table 1 Demographic and clinical characteristics according to gender

	All	Female	Male	P value
Number	4880	2363	2517
Age, years, mean ± SD	38.70 ± 11.55	39.07 ± 11.49	38.35 ± 11.59	0.0271
< 45	3175 (65.06)	1506 (63.73)	1669 (66.31)	0.059
≥ 45	1705 (34.94)	857 (36.27)	848 (33.69)
Race, n (%)				0.278
Non-Hispanic White	1993 (40.84)	951 (40.25)	1042 (41.40)
Non-Hispanic Black	1057 (21.66)	537 (22.73)	520 (20.66)
Mexican American	581 (11.91)	269 (11.38)	312 (12.40)
Other Race/ethnicity	1249 (25.59)	606 (25.65)	643 (25.55)
Education level, n (%)				< 0.001
Below high school	796 (16.31)	346 (14.64)	450 (17.88)
High school	1037 (21.25)	442 (18.71)	595 (23.64)
College or above	3047 (62.44)	1575 (66.65)	1472 (58.48)
Marital status, n (%)				0.091
Other	2562 (52.50)	1270 (53.75)	1292 (51.33)
Married	2318 (47.50)	1093 (46.25)	1225 (48.67)
Poverty income ratio, mean ± SD	2.53 ± 1.69	2.51 ± 1.69	2.55 ± 1.68	0.3031
≤ 1, n (%)	1166 (23.89)	584 (24.71)	582 (24.71)	< 0.001
> 1, n (%)	3714 (76.11)	1779 (75.29)	1935 (24.71)
Body mass index, kg/m2	28.72 ± 6.87	29.24 ± 7.59	28.23 ± 6.08	0.0021
< 25, n (%)	1592 (32.6)	793 (33.56)	799 (31.74)	< 0.001
≥ 25, n (%)	2288 (67.3)	1570 (66.44)	1718 (68.26)
Muscle quality index, mean ± SD	3.38 ± 0.63	3.28 ± 0.64	3.47 ± 0.61	< 0.0011
Recreational activity, n (%)				< 0.001
None	2121 (43.46)	1078 (45.62)	1043 (41.44)
Moderate	1281 (26.25)	715 (30.26)	566 (22.49)
Vigorous	557 (11.41)	198 (8.38)	359 (14.26)
Both	921 (18.87)	372 (15.74)	549 (21.81)
Smoke, n (%)				< 0.001
Never	2887 (59.16)	1557 (65.89)	1330 (52.84)
Former	814 (16.68)	325 (13.75)	489 (19.43)
Now	1179 (24.16)	481 (20.36)	698 (27.73)
Hypertension, n (%)				0.629
No	3578 (73.32)	1740 (73.64)	1838 (73.02)
Yes	1302 (26.68)	623 (26.36)	679 (26.98)
Hyperlipidemia, n (%)				0.008
No	1903 (39.00)	876 (37.07)	1027 (40.80)
Yes	2977 (61.00)	1487 (62.93)	1490 (59.20)
Diabetes, n (%)				0.182
No	4511 (92.44)	2172 (91.92)	2339 (92.93)
Yes	369 (7.56)	191 (8.08)	178 (7.07)
Cardiovascular disease, n (%)				0.973
No	4704 (96.39)	2278 (96.40)	2426 (96.38)
Yes	176 (3.61)	85 (3.60)	91 (3.62)
Cancer, n (%)				< 0.001
No	4688 (96.07)	2240 (94.79)	2448 (97.26)
Yes	192 (3.93)	123 (5.21)	69 (2.74)
Depression, n (%)				< 0.001
No	4468 (91.56)	2094 (88.62)	2374 (94.32)
Yes	412 (8.44)	269 (11.38)	143 (5.68)

¹P value: Kruskal-Wallis rank test for continuous variables, Fisher exact for categorical variables with expects < 10.

Table 2 Weighted logistic regression analysis of muscle quality index with depression

		All		Male		Female		P value1
		OR (95%CI)	P value	OR (95%CI)	P value	OR (95%CI)	P value
Model I	Muscle quality index	0.66 (0.52-0.84)	0.0018	1.03 (0.74-1.44)	0.8490	0.59 (0.42-0.81)	0.0035	0.0201
	Muscle quality index group							0.0109
	1.12-3.38	Reference		Reference		Reference
	3.38-5.83	0.68 (0.55-0.84)	0.0011	1.18 (0.84-1.65)	0.3403	0.55 (0.38-0.80)	0.0035
Model II	Muscle quality index	0.73 (0.58-0.91)	0.0121	0.97 (0.71-1.33)	0.8437	0.62 (0.45-0.86)	0.0098	0.0689
	Muscle quality index group							0.0239
	1.12-3.38	Reference		Reference		Reference
	3.38-5.83	0.75 (0.61-0.92)	0.0106	1.14 (0.83-1.57)	0.4308	0.57 (0.39-0.84)	0.0091
Model III	Muscle quality index	0.81 (0.63-1.04)	0.1321	1.08 (0.77-1.52)	0.6586	0.68 (0.49-0.95)	0.0482	0.0454
	Muscle quality index group							0.0124
	1.12-3.38	Reference		Reference		Reference
	3.38-5.83	0.83 (0.63-1.09)	0.2001	1.29 (0.89-1.88)	0.2053	0.61 (0.41-0.92)	0.0402

¹Global χ² test for interaction terms (exposure: Gender).

Model I adjust for none. Model II adjust for age, gender, race, marital, educational level. Model III adjust for age, race, marital, educational level, smoke, diabetes, hypertension, hyperlipidemia, cardiovascular disease, cancer, body mass index, recreational activity, poverty income ratio. OR: Odds ratio; CI: Confidence interval.

Table 3 Threshold analysis

	OR (95%CI)	P value
Turning point (K)		2.21
< K effect 1	0.20 (0.14-0.64)	0.008
> K effect 2	0.79 (0.63-1.05)	0.086
Effect 2-1	4.27 (1.11-16.90)	0.036
Model fit value at K	-1.64 (-1.93 to -1.38)
LRT test		0.041
95%CI of TP(K)	2.21-2.50

Threshold analysis was adjusted for age, race, marital, educational level, smoke, diabetes, hypertension, hyperlipidemia, cardiovascular disease, cancer, body mass index, recreational activity, poverty income ratio. OR: Odds ratio; CI: Confidence interval; LRT: Likelihood ratio test; TP: Turning point.