Chemical Intolerance in Primary Care Settings: Prevalence, Comorbidity, and Outcomes

Article Figures & Data

Table 1

Patient Characteristics (N = 400)

Characteristic	Patients, No. (%)
Clinic
University Health Center–Downtown	270 (68)
Leonard G. Paul Family Health Center	130 (33)
Sex
Male	148 (37)
Female	252 (63)
Ethnicity
Hispanic	343 (86)
Non-Hispanic white	57 (14)
Education^a
Less than high school	125 (32)
High school graduate	102 (26)
Some college	168 (43)
Income^a
<$20,000	205 (68)
$20,000–$40,000	68 (23)
>$40,000	29 (7)
Social class^a,^b
I	3 (1)
II	19 (5)
III	87 (22)
IV	51 (13)
V	235 (60)

↵a Missing excluded.
↵b Based on Hollingshead and Redlich.⁴⁶ Class I is highest socioeconomic status.

Table 2

Odds of a Personal History and Family History of Conditions by Chemical Intolerance Status

	Personal History^a			Family History^a

Condition	Chemically Intolerant (n = 81)	Chemically Tolerant (n = 319)	Odds Ratio (95% CI)	Chemically Intolerant (n = 81)	Chemically Tolerant (n = 319)	Odds Ratio (95% CI)
Asthma	14 (17)	34 (11)	1.75 (0.89–3.45)	22 (27)	59 (19)	1.64 (0.93–2.89)
Allergies	43 (53)	129 (40)	1.67 (1.02–2.72)^b	36 (44)	132 (41)	1.13 (0.69–1.85)
Autism	1 (1.2)	1 (0.3)	3.98 (0.25–64.24)	2 (3)	8 (3)	0.98 (0.21–4.73)
Multiple sclerosis	0 (0)	2 (0.6)	–	1 (1)	7 (2)	0.56 (0.07–4.59)
Arthritis	27 (33)	75 (24)	1.63 (0.96–2.76)	31 (38)	97 (30)	1.42 (0.85–2.36)
Diabetes	22 (27)	63 (20)	1.52 (0.86–2.66)	39 (48)	122 (38)	1.50 (0.92–2.45)
Gastrointestinal disorder	14 (17)	54 (17)	1.03 (0.54–1.96)	21 (26)	31 (10)	3.25 (1.75–6.04)^b
Mood disorder	44 (54)	64 (20)	4.74 (2.83–7.94)^b	31 (38)	56 (18)	2.92 (1.71–4.96)^b
Chemical intolerance	19 (24)	24 (8)	3.77 (1.94–7.30)^b	16 (20)	24 (8)	3.03 (1.52–6.02)^b
Systemic lupus erythematosus	3 (4)	5 (2)	2.42 (0.57–10.33)	7 (9)	9 (3)	3.26 (1.18–9.03)^b

Table 3

Odds of Symptoms of Mental Disorders by Chemical Intolerance Status

Disorder^a	Chemically Intolerant, No. (%) (n = 81)	Chemically Tolerant, No. (%) (n = 319)	Odds Ratio (95% CI)
Major depressive disorder	69 (85)	106 (33)	11.55 (6.00–22.26)^b
Generalized anxiety disorder	63 (78)	67 (21)	13.16 (7.30–23.73)^b
Panic disorder	44 (54)	53 (17)	5.97 (3.52–10.11)^b
Alcohol abuse disorder	30 (37)	63 (20)	2.39 (1.41–4.06)^b
Somatization disorder	74 (91)	218 (68)	4.90 (2.18–11.01)^b

↵a Symptoms of the disorder were assessed with the Primary Care Evaluation of Mental Disorders Patient Questionnaire.
↵b Significant odds ratio.

Table 4

Functional Status and Health Care Use by Chemical Intolerance Status

	Model 1^a			Model 2^b

Variable	Chemically Intolerant (n = 81)	Chemically Tolerant (n = 319)	F (P Value)	Chemically Intolerant (n = 81)	Chemically Tolerant (n = 319)	F (P Value)
Limitations in functional status in past month^c
Daily activities	3.17	2.27	39.31 (<.001)	2.69	2.39	3.61 (.058)
Social activities	3.02	1.95	54.60 (<.001)	2.46	2.09	5.42 (.02)
Social support	2.71	2.20	10.45 (.001)	2.32	2.30	0.02 (.88)
Feelings	3.11	2.07	51.15 (<.001)	2.26	2.28	0.02 (.90)
Physical fitness	3.32	2.92	6.20 (.01)	3.11	2.97	0.50 (.48)
Pain	3.51	2.75	24.51 (<.001)	3.05	2.87	1.06 (.30)
Overall health	3.66	2.84	44.39 (<.001)	3.11	2.98	1.07 (.30)
Quality of life	3.06	2.51	22.28 (<.001)	2.59	2.63	0.13 (.72)
Health care use, number in past 2 months
Emergency services	1.22	0.43	7.57 (.006)	1.04	0.47	2.78 (.09)
Primary care offices	2.06	2.04	0.01 (.94)	1.90	2.08	0.25 (.62)
Specialty offices	0.74	0.42	3.80 (.052)	0.72	0.42	2.47 (.12)
Mental health services	0.61	0.34	2.44 (.12)	0.17	0.45	2.10 (.15)
Total ambulatory use	4.63	3.22	5.00 (.03)	3.83	3.42	0.32 (.57)
Hospitalizations, number in past year	1.14	0.51	5.90 (.02)	0.88	0.57	1.03 (.31)

Note: Values are multivariate analysis of variance (MANOVA) means adjusted for demographics and symptoms of mental disorders, unless otherwise noted.
↵a Adjusted for age, sex, and socioeconomic status; Wilk l = .797, F = 5.98 (P <.001).
↵b Adjusted for age, sex, socioeconomic status, and symptoms of depression, generalized anxiety disorder, panic disorder, and alcohol abuse disorder; Wilk l = .936, F = 1.58 (P=.07).
↵c Assessed with the Dartmouth–Northern New England Primary Care Cooperative Information Project (Dartmouth COOP) charts. Each scale has a possible score of 1 to 5, where 5 = greatest impairment.