Genotype-dependent associations between serotonin transporter gene (SLC6A4) DNA methylation and late-life depression

Table 1 Characteristics of study participants according to depression status

Characteristic^a	No depression	Depression	p- value^g
n	207	95	–
Age (Mean ± S.D.)	72.5 ± 5.2	74.6 ± 5.7	0.004
	Proportion (%)
Female	55.1	68.4	0.028
Past major depressive disorder	25.3	38.6	0.062
High education level^b	38.2	25.3	0.028
Living alone	20.9	43.2	< 0.001
Habitual alcohol drinkers (> 24 g/day)	19.2	20.4	0.81
Habitual smokers (≥10 pack years)	35.6	34.4	0.84
Functional impairment^c	5.31	13.7	0.013
Ischemic disease^d	10.6	22.1	0.008
Comorbidities^e	12.1	29.5	< 0.001
Anxiety	15.9	29.5	0.044
Dementia	4.3	2.1	0.334
Impaired cognition (MMSE< 26)^f	13.6	11.6	0.63
Antidepressants	3.38	12.6	0.002
Selective serotonin re-uptake inhibitor (SSRI)	2.90	6.3	0.158
Tricyclic antidepressant (TCA)	0.48	2.10	0.187
Other antidepressants	0.00	4.20	0.003
Benzodiazepines	4.83	9.47	0.123
Anxiolytics	7.73	16.8	0.017
Psychotropic drugs	4.83	11.6	0.032
Anticholinergics	4.83	7.37	0.374

^aNot all participants with methylation data (n = 302) had information for each population characteristic listed, but missing data was < 2%, with exception of anxiety (20.5%) and past MDD (33%)
^bUnderwent post-secondary education of any type
^cUnable to independently complete 2 items on both or either of the Instrumental Activities of Daily Living and Activities of Daily Living scales
^dHistory of angina pectoris, myocardial infarction, stroke, cardiovascular surgery and/or arteritis
^eHypertension (resting blood pressure ≥ 160/95 mmHg), high cholesterol (total cholesterol ≥6.2 mmol/l), diabetes (fasting glucose ≥7.0 mmol/l), thyroid disease, asthma, or recent cancer diagnosed within the last 2 years
^fMMSE: Mini-Mental State Examination
^gChi-squared tests used to assess p-value for all variables except age, where a t-test was used

ISSN: 1471-244X