Alcohol intolerance and myalgic encephalomyelitis/chronic fatigue syndrome

Table 1 DePaul symptom questionnaire-2 questions used to classify alcohol intolerance

Question	Response options
Severity: Throughout the past 6 months, how much has alcohol intolerance bothered you?	0 = symptom not present
	1 = mild
	2 = moderate
	3 = severe
	4 = very severe
Over the last 6 months, did you avoid alcohol due to an alcohol intolerance (feeling sick after drinking alcohol)?	Yes
	No, I drank alcohol
	No, I do not drink alcohol for other reasons
If you were to drink alcohol, how severe would the intolerance be?	0 = symptom not present
	1 = mild
	2 = moderate
	3 = severe
	4 = very severe

Table 2 Demographic characteristics of the sample (n = 304) separated by binary alcohol intolerance classification

Characteristic	Alcohol intolerant, n = 208		Not alcohol intolerant, n = 96
	mean (%)	SD or n	mean (%)	SD or n
Age	48.07	12.26	49.57	13.50
Sex
Male	11.1	23	8.3	8
Female	87.5	182	88.5	85
Race
White	95.2	198	99.0	95
Asian or Pacific Islander	1.4	3	1.0	1
Other	2.9	6	0	0
Latinx
No	98.1	204	96.9	93
Yes	1.4	3	3.1	3
Education
High school diploma or less	12.0	25	9.4	9
College degree or partial college	46.2	96	55.3	53
Graduate degree	41.3	86	34.4	33
Work status
On disability	50.0	104	40.6	39
Working (full-time or part-time)	25.5	53	29.2	28
Retired	8.7	18	13.5	13
Unemployed	16.3	34	11.5	11
Student or homemaker	9.6	20	12.6	12
Marital status
Married or living with partner	45.2	94	55.2	53
Never married	31.7	66	25.0	24
Divorced	16.8	35	14.6	14
Widowed	1.9	4	3.1	3
Separated	2.9	6	2.1	2

Table 3 Differences in composite DePaul symptom questionnaire-2 symptom scores

Symptom	Alcohol intolerant	Not alcohol intolerant	P value
	mean (SD)	mean (SD)
Post-exertional malaise	79.53 (15.46)	71.99 (17.07)	< 0.01
Feeling drained	74.70 (21.53)	67.06 (23.31)	0.01
Minimum exercise	78.99 (20.48)	72.27 (20.62)	0.01
Worse after physical activity	80.83 (21.42)	74.22 (21.83)	0.01
Soreness	77.84 (19.87)	70.96 (20.40)	0.01
Fatigue	81.86 (15.10)	77.47 (15.88)	0.02
Heavy feeling	83.87 (22.56)	69.53 (30.82)	< 0.01
Muscle fatigue	76.80 (24.01)	64.32 (26.03)	< 0.01
Unrefreshing sleep	81.52 (18.83)	80.08 (20.80)	0.57
Cognitive impairment	61.53 (18.28)	54.92 (18.39)	< 0.01
Difficulty remembering	68.84 (22.51)	64.58 (25.17)	0.14
Difficulty finding right word	61.78 (23.69)	54.56 (23.02)	0.01
Difficulty understanding	51.02 (24.93)	44.14 (24.33)	0.02
Absent-mindedness	62.74 (24.94)	57.50 (22.73)	0.08
Slowness of thought	60.34 (24.78)	52.99 (25.70)	0.02
Only focus on one thing	68.96 (23.14)	59.38 (24.60)	< 0.01
Difficulty paying attention	72.84 (23.31)	66.97 (23.77)	0.04
Slowed speech	35.75 (27.80)	29.61 (24.33)	0.07
Mental tiredness	71.32 (21.74)	64.19 (23.55)	0.01
Fever and flu	37.71 (19.81)	33.74 (19.55)	0.1
Fever	16.36 (21.41)	14.71 (20.52)	0.53
High temperature	33.82 (26.14)	29.43 (26.09)	0.18
Flu-like symptoms	52.84 (25.87)	49.22 (27.97)	0.27
Prolonged viral illness recovery	38.16 (32.95)	35.68 (33.88)	0.55
Fluctuations in temperature	47.18 (31.83)	39.76 (31.38)	0.06
Pain	54.84 (22.94)	46.30 (21.86)	< 0.01
Stomach pain	45.11 (28.08)	36.33 (25.14)	0.01
Irritable bowel	51.98 (31.39)	44.01 (31.88)	0.04
Bloating	50.79 (28.83)	41.45 (25.80)	0.01
Muscle pain	71.45 (25.12)	63.15 (29.43)	0.02
Sleep disruption	57.63 (23.80)	51.52 (25.12)	0.04
Problems staying asleep	61.29 (28.62)	54.04 (29.16)	0.04
Waking up early	52.40 (28.64)	44.53 (30.07)	0.03
Problems falling asleep	61.29 (28.62)	54.04 (29.16)	0.39
Orthostatic intolerance	39.99 (23.21)	27.86 (22.93)	< 0.01
Graying or blacking out after standing	28.14 (29.39)	17.63 (24.90)	< 0.01
Blurred or tunnel vision after standing	35.52 (31.01)	25.13 (28.51)	0.01
Heart beats quickly after standing	50.12 (31.11)	35.66 (33.37)	< 0.01
Dizziness	45.91 (26.21)	33.85 (26.34)	< 0.01
Genitourinary	43.06 (26.18)	36.81 (23.43)	0.05
Urinary urgency	41.95 (30.88)	38.03 (31.99)	0.31
Bladder problems	36.96 (31.91)	29.82 (27.29)	0.05
Nighttime urinary urgency	50.18 (31.51)	42.37 (30.20)	0.04
Temperature intolerance	39.45 (22.76)	28.60 (19.98)	< 0.01
Chills or shivers	37.38 (26.16)	27.34 (24.01)	< 0.01
Low temperature	29.41 (28.02)	17.45 (20.80)	< 0.01
Cold limbs	51.02 (28.65)	41.02 (28.89)	0.01
Other
Needing to nap daily	58.74 (28.63)	53.39 (30.80)	0.14
Sleep inversion	21.80 (30.09)	16.28 (26.85)	0.11
Joint pain	60.33 (31.88)	56.64 (30.99)	0.35
Eye pain	34.24 (29.25)	25.52 (25.32)	0.01
Chest pain	28.32 (23.57)	19.79 (24.24)	< 0.01
Headaches	53.32 (26.10)	45.18 (24.69)	0.01
Twitching	38.28 (26.15)	30.34 (24.25)	0.01
Muscle weakness	68.15 (25.56)	57.81 (25.92)	< 0.01
Sensitivity to noise	64.12 (25.50)	57.55 (27.95)	0.04
Sensitivity to light	58.53 (28.25)	51.04 (29.00)	0.03
Unable to focus vision	41.35 (26.21)	33.06 (22.82)	0.01
Unable to focus attention	56.63 (21.10)	53.89 (20.75)	0.31
Loss of depth perception	31.10 (31.76)	17.63 (24.22)	< 0.01
Nausea	39.42 (24.74)	26.04 (25.76)	< 0.01
Feeling unsteady	49.70 (28.00)	36.85 (25.48)	< 0.01
Shortness of breath	38.88 (27.26)	35.81 (26.07)	0.36
Irregular heartbeat	32.91 (26.82)	28.26 (26.79)	0.16
Losing weight	19.04 (25.04)	17.34 (19.65)	0.6
Gaining weight	52.70 (33.53)	47.58 (31.51)	0.3
Loss of appetite	30.37 (24.52)	31.12 (25.84)	0.81
Sweating hands	15.99 (23.28)	15.89 (24.97)	0.97
Night sweats	37.44 (29.32)	35.55 (30.20)	0.61
Feeling hot or cold	53.93 (26.88)	45.96 (26.93)	0.02
Sore throats	37.50 (25.00)	32.16 (24.11)	0.08
Lymph nodes	39.54 (28.82)	34.08 (27.50)	0.12
Sensitivity to smells	53.43 (30.68)	37.50 (30.99)	< 0.01
Sensitivity to mold	29.89 (37.74)	21.45 (29.94)	0.04
Temperature intolerance	72.52 (26.97)	55.60 (31.93)	< 0.01
Worse after mental activity	66.41 (24.31)	59.87 (28.53)	0.06
Feeling disoriented	40.44 (25.23)	33.68 (23.36)	0.03
Difficulty reading	50.96 (32.42)	39.34 (30.89)	< 0.01
Eye aching	40.44 (29.61)	30.66 (28.47)	0.01
Sensitivity to pain	53.50 (31.78)	44.35 (36.19)	0.04
Pain from pressure	27.00 (34.21)	24.87 (33.73)	0.62
Daytime drowsiness	64.24 (26.74)	60.53 (27.85)	0.27
Sensitivity to vibrations	36.34 (35.50)	21.68 (31.39)	< 0.01
Poor coordination	51.68 (28.56)	38.42 (25.08)	< 0.01
Sinus infections	25.00 (28.84)	23.68 (25.36)	0.69
Upright position intolerance	51.98 (32.87)	44.08 (32.86)	0.05

Table 4 Differences for short form-36 domain scores

Domain	Alcohol intolerant	Not alcohol intolerant	P value
	mean (SD)	mean (SD)
Physical functioning	23.91 (20.45)	34.27 (21.86)	< 0.01
Role physical	2.00 (9.39)	4.39 (11.22)	0.12
Bodily pain	34.30 (22.50)	43.82 (26.36)	< 0.01
General health	23.28 (15.02)	25.51 (14.36)	0.29
Vitality	8.98 (10.74)	12.47 (13.75)	0.06
Social functioning	18.34 (20.03)	25.51 (22.38)	0.02
Role emotional	69.54 (42.15)	63.01 (43.94)	0.29
Mental health	67.08 (18.84)	66.48 (20.00)	0.83

Table 5 Linear regression for symptom domain scores, sex, and age

Feature	Unstandardized coefficients		Standardized coefficients	t	P	95%CI
	B	SE	Beta			LL	UL
Constant	0.90	0.70	< 0.01	1.29	0.20	-0.47	2.27
Sex	-0.27	0.27	-0.06	-1.01	0.31	-0.79	0.25
Age	< 0.01	0.01	0.04	0.57	0.57	-0.01	0.02
PEM domain	0.01	0.01	0.15	1.82	0.07	0.00	0.02
Cognitive impairment domain	< 0.01	0.01	-0.04	-0.54	0.59	-0.01	0.01
Fever/flu-like symptoms domain	-0.01	0.01	-0.11	-1.39	0.16	-0.02	0.00
Pain domain	< 0.01	< 0.01	0.07	0.89	0.37	0.00	0.01
Sleep disruption domain	< 0.01	< 0.01	-0.03	-0.43	0.67	-0.01	0.01
Orthostatic intolerance domain	0.01	< 0.01	0.21	2.57	0.01	0.00	0.02
Genitourinary domain	0.01	< 0.01	0.12	1.73	0.08	0.00	0.01
Temperature intolerance domain	0.01	< 0.01	0.09	1.11	0.27	0.00	0.01

CI: Confidence interval; LL: Lower limit of the confidence interval; PEM: Post-exertional malaise; UL: Upper limit of the confidence interval.