Epigenetic biomarkers of ageing are predictive of mortality risk in a longitudinal clinical cohort of individuals diagnosed with oropharyngeal cancer

Table 2 Baseline characteristics of the study sample stratified by 3-year mortality status (n = 408)

Characteristic	Overall (n = 408)		Dead at 3 years (n = 77)		Alive at 3 years		p value
	Overall (n = 408)		Dead at 3 years (n = 77)		(n = 331)
	N	%	N	%	N	%
Sex
Male	317	77.70	60	77.90	257	77.60
Female	91	22.30	17	22.10	74	22.40	0.958
TNM stage group
I	17	4.20	1	1.30	16	4.80
II	39	9.60	4	5.20	35	10.60
III	58	14.20	14	18.20	44	13.30
IV	294	72.10	58	75.30	236	71.30	0.175
HPV status
Negative	122	29.90	45	58.40	77	23.30
Positive	286	70.10	32	41.60	254	76.70	< 0.001
Comorbidity status*
None	211	52.10	26	34.20	185	56.20
Mild	119	29.40	27	35.50	92	28.00
Moderate/severe	75	18.50	23	30.30	52	15.80	0.001
Smoking
Never	110	28.10	8	11.00	102	32.00
Former	205	52.30	40	54.80	165	51.70
Current	77	19.60	25	34.20	52	16.30	< 0.001
Alcohol
Non-drinker	104	26.00	14	18.90	90	27.60
Moderate	90	22.50	11	14.90	79	24.20
Hazardous/harmful	206	51.50	49	66.20	157	48.20	0.019
Education
School education	170	43.70	37	50.00	133	42.20
College	158	40.60	28	37.80	130	41.30
Degree	61	15.70	9	12.20	52	16.50	0.422
Annual household income
< £18,000	138	38.70	36	56.30	102	34.80
£18,000–£34,999	103	28.90	13	20.30	90	30.70
> £35,000	116	32.50	15	23.40	101	34.50	0.006
Marital status
Single (never married)	47	11.70	11	14.70	36	11.00
Currently in relationship	280	69.70	38	50.70	242	74.00
No longer with spouse	75	18.70	26	34.00	49	15.00	< 0.001

	N	Mean (SD)**	N	Mean (SD)**	N	Mean (SD)**	p value
Age at baseline	403	58.4 (9.6)	77	62.86 (11.25)	326	57.39 (8.91)	< 0.001
Body mass index	272	26.4 (4.9)	46	24.33 (4.76)	226	26.88 (4.87)	0.001
EEAA	408	− 0.03 (5.78)	77	1.68 (6.52)	331	− 0.42 (5.53)	0.004
IEAA	408	− 0.07 (4.37)	77	0.36 (4.34)	331	− 0.17 (4.38)	0.333
IEAAHannum	408	− 0.01 (3.94)	77	1.10 (4.52)	331	− 0.27 (3.76)	0.006
AgeAccelGrim	408	− 0.10 (5.61)	77	3.16 (5.37)	331	− 0.86 (5.40)	< 0.001
AgeAccelPheno	408	− 0.12 (6.57)	77	2.00 (7.04)	331	− 0.62 (6.36)	0.002
ZhangScore	408	− 2.20 (0.28)	77	− 2.15 (0.29)	331	− 2.21 (0.27)	0.096

EEAA, extrinsic epigenetic age acceleration; IEAA, intrinsic epigenetic age acceleration, TNM, Tumour, Node, Metastasis. P value for difference based on the chi-squared test (categorical) and one-way ANOVA (continuous). * Based on the Adult Comorbidity Evaluation-27 (ACE-27). **For the epigenetic clock measures (IEAA, IEAAHannum, EEAA, AgeAccelPheno and AgeAccelGrim), mean values represent the difference in chronological age and age predicted by the clock, e.g. a mean value of 1.68 indicates that, on average, people who had died at 3 years were predicted to be 1.68 years older than their chronological age at baseline based on their epigenome. A mean age value of − 0.42 indicates that people who were still alive at 3 years were predicted to be, on average, 0.42 years younger than their chronological age. The mortality risk score (ZhangScore), values represent methylation values (rather than years)

ISSN: 1868-7083