. 2021 Jan 9;36(3):311–318. doi: 10.1007/s10654-020-00709-1

Table 4.

Sensitivity analysis for the association between serum IGF-1 concentrations and COVID-19 mortality with adjustment for waist circumference instead of body mass index

	Quartile of log-transformed IGF-1 levels, OR (95% CI)^a				P-trend^b	OR per 1-SD increment^c	Adjusted OR per 1-SD increment^d
	Q1	Q2	Q3	Q4	P-trend^b	OR per 1-SD increment^c	Adjusted OR per 1-SD increment^d
No. of cases	142	105	100	68
Model 1	Ref	0.70 (0.50–0.97)	0.76 (0.55–1.07)	0.53 (0.37–0.77)	0.001	0.84 (0.74–0.95)	0.80 (0.68–0.94)
Model 2	Ref	0.74 (0.53–1.04)	0.86 (0.61–1.21)	0.59 (0.40–0.85)	0.01	0.88 (0.78–0.99)	0.85 (0.72–0.99)
Model 2 plus other factors^e	Ref	0.71 (0.49–1.03)	0.92 (0.64–1.33)	0.56 (0.37–0.84)	0.02	0.86 (0.74–0.98)	0.82 (0.68–0.98)

OR, odds ratio; CI, confidence interval; Ref, reference

^aModel 1: adjusted for age at infection, sex, ethnicity. Model 2: additionally adjusted for Townsend deprivation index, waist circumference, smoking status, alcohol drinking, physical activity, and prevalent diabetes

^bP-trend was based on the median value of each quartile of log-transformed IGF-1 levels as a continuous variable in the models

^cSD was the standard deviation of log-transformed IGF-1 levels, which was 0.30

^dORs per SD increment were additionally corrected for the intraclass correlation coefficient (0.78) obtained from the subsample of participants with repeat IGF-1 measurements

^eModel 2 plus additional adjustment for serum glucose, cardiovascular risk factors (serum lipids, blood pressure, cholesterol lowering and antihypertensive medications), and C-reactive protein. A total of 236 participants had missing data on serum glucose, lipids, or C-reactive protein