Table 4.

Association of severe hair loss with diabetes in strata of BMI, use of hair extensions or weaves, use of hair relaxers, mother’s hair loss, and father’s hair loss

	Cases/person-years	Multivariable HR⁎ (95% CI)
BMI
BMI < 30
No diabetes	375/55499	1.0
Diabetes	43/1746	2.12 (1.51-2.96)
BMI 30-34
No diabetes	175/17364	1.0
Diabetes	30/1535	1.37 (0.90-2.08)
BMI 35-39
No diabetes	84/8752	1.0
Diabetes	27/1220	2.18 (1.36-3.49)
BMI 40 +
No diabetes	74/6664	1.0
Diabetes	29/1262	1.67 (1.04-2.67)
P for interaction		0.40
Use of hair weaves or extensions
Never used weaves/extensions
No diabetes	473/70131	1.0
Diabetes	79/4441	1.56 (1.21-2.01)
Ever used weave/extensions
No diabetes	220/16136	1.0
Diabetes	44/1251	1.50 (1.05-2.14)
P for interaction		0.54
Use of hair relaxer
Used hair relaxer < 6 years
No diabetes	104/11962	1.0
Diabetes	18/768	1.97 (1.13-3.43)
Used hair relaxer ≥ 6 years
No diabetes	597/75485	1.0
Diabetes	108/4970	1.65 (1.32-2.05)
P for interaction		0.94
Hair loss in participant’s mother
Mother had no hair loss
No diabetes	142/29868	1.0
Yes diabetes	33/2101	1.85 (1.21-2.82)
Mother had mild hair loss
No diabetes	157/25505	1.0
Diabetes	27/1508	1.92 (1.22-3.01)
Mother had severe hair loss
No diabetes	296/19342	1.0
Diabetes	49/1239	1.54 (1.10-2.16)
P for interaction		0.68
Hair loss in participant’s father
Father had no hair loss
No diabetes	183/32412	1.0
Yes diabetes	44/2130	2.37 (1.64-3.41)
Father had mild hair loss
No diabetes	160/18391	1.0
Diabetes	33/1315	1.57 (1.03 -2.39)
Father had severe hair loss
No diabetes	201/20661	1.0
Diabetes	23/1177	1.21 (0.76-1.94)
P for interaction		0.07

BMI, body mass index; CI, confidence interval; HR, hazard ratio

^⁎Adjusted for age (continuous), BMI (< 25, 25-29, 30-34, 35-39, ≥ 40, unknown), except in strata of BMI where it is included as a continuous variable, and years of education (≤ 12, 13-15, 16, ≥ 17)