Reduced risk of dementia in patients with type 2 diabetes mellitus using Chinese herbal medicine: A nested case-control study

Table 1 Demographic data and selected comorbidities of the two study groups

Variables	Number (%)	Cases	Controls	P value
		n = 11699 (%)	n = 11699 (%)
Age (yr)				0.07
20-40	2307 (9.9)	1139 (9.7)	1168 (10.0)
41-60	16457 (70.3)	8174 (69.9)	8283 (70.8)
61-70	4634 (19.8)	2386 (20.4)	2248 (19.2)
mean ± SD	51.6 ± 7.3	51.5 ± 7.2	51.6 ± 7.3	0.34
Duration of follow-up, yr (SD)	5.8 (3.4)	6.4 (3.2)	5.5 (3.4)
Sex				0.99
Female	11243 (48.1)	5622 (48.1)	5621 (48.0)
Male	12155 (51.9)	6077 (51.9)	6078 (52.0)
Monthly income				0.15
Low	8561 (36.5)	4290 (36.7)	4271 (36.5)
Median	13116 (56.1)	6587 (56.3)	6529 (55.8)
High	1721 (7.4)	822 (7.0)	899 (7.7)
Residential area				0.19
Urban	14005 (59.8)	6939 (59.3)	7066 (60.4)
Suburban	3718 (15.9)	1869 (16.0)	1849 (15.8)
Rural	5675 (24.3)	2891 (24.7)	2784 (23.8)
CCI	4.3 (5.7)	4.3 (5.8)	4.3 (5.6)	0.68

SD: Standard deviation; CCI: Charlson-Deyo comorbidity index.

Table 2 The association between dementia onset and use of Chinese herbal medicine among type 2 diabetes mellitus patients

CHM exposure	Patients				Crude OR (95%CI)	Adjusted OR1 (95%CI)
	Cases, n = 11699		Controls, n = 11699
Non-CHM users	9053	77.4	7533	64.4	1	1
CHM users	2646	22.6	4166	35.6	0.53 (0.50-0.56)	0.51 (0.48-0.53)
Low intensity (31-365 d)	2350	20.1	3366	28.8	0.58 (0.55-0.62)	0.57 (0.53-0.60)
Medium intensity (366-730 d)	206	1.8	482	4.1	0.35 (0.30-0.42)	0.33 (0.28-0.39)
High intensity (731 d or more)	90	0.8	318	2.7	0.24 (0.19-0.30)	0.22 (0.17-0.28)

¹Adjusted for potential confounders that contained age, residential area, monthly income and Charlson-Deyo comorbidity index.

CHM: Chinese herbal medicine; OR: odds ratio; CI: Confidence interval.

Table 3 Risk of dementia among type 2 diabetes mellitus patients with and without exposure to Chinese herbal medicine use stratified by sex and age

Variables	Patients, n (%)	Crude OR (95%CI)	Adjusted OR (95%CI)
Female
Non-CHM users	4140 (73.6)	1	1
CHM users	1482 (26.4)	0.51 (0.47-0.55)	0.49 (0.45-0.53)1
Male
Non-CHM users	4913 (80.8)	1	1
CHM users	1164 (19.2)	0.54 (0.50-0.59)	0.53 (0.48-0.57)1
Aged 20-40 yr
Non-CHM users	1011 (77.6)	1	1
CHM users	291 (22.4)	0.46 (0.39-0.55)	0.45 (0.37-0.54)2
Aged 41-60 yr
Non-CHM users	6487 (77.2)	1	1
CHM users	1921 (22.8)	0.53 (0.49-0.57)	0.51 (0.48-0.55)2
Aged 61-70 yr
Non-CHM users	1555 (78.2)	1	1
CHM users	434 (21.8)	0.54 (0.47-0.61)	0.53 (0.46-0.60)2

¹Adjusted for the age, residential area, monthly income and Charlson-Deyo comorbidity index.

²Adjusted for the sex, residential area, monthly income and Charlson-Deyo comorbidity index.

CHM: Chinese herbal medicine; OR: Odds ratio; CI: Confidence interval.