Chronic fatigue syndrome and high allostatic load: results from a population-based case-control study in Georgia.
OBJECTIVE
To confirm the association of chronic fatigue syndrome (CFS) with high allostatic load (AL) level, examine the association of subsyndromal CFS with AL level, and investigate the effect of depression on these relationships and the association of AL with functional impairment, fatigue, symptom severity, fatigue duration, and type of CFS onset. AL represents the cumulative physiologic effect of demands to adapt to stress.


METHODS
Population-based case-control study of 83 persons with CFS, 202 persons with insufficient symptoms or fatigue for CFS (ISF), and 109 well controls living in Georgia. Unconditional logistic regression was used to generate odds ratios (ORs) as measures of the association of AL with CFS.


RESULTS
Relative to well controls, each 1-point increase in allostatic load index (ALI) was associated with a 26% increase in likelihood of having CFS (OR(adjusted) = 1.26, 95% Confidence Interval (CI) = 1.00, 1.59). This association remained in the presence and absence of depression (OR(adjusted) = 1.35, CI = 1.07, 1.72; OR(adjusted) = 1.35, CI = 1.10, 1.65). Compared with the ISF group, each 1-point increase in ALI was associated with a 10% increase in likelihood of having CFS (OR(adjusted) = 1.10, CI = 0.93, 1.31). Among persons with CFS, the duration of fatigue was inversely correlated with ALI (r = -.26, p = .047).


CONCLUSIONS
Compared with well controls, persons with CFS were significantly more likely to have a high AL. AL increased in a gradient across well, ISF, and CFS groups.
Maloney
Elizabeth M
EM
Chronic Viral Diseases Branch, National Center for Zoonotic, Vector-borne and Enteric Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS A-15, Atlanta, GA 30333, USA. evm3@cdc.gov
Boneva
Roumiana
R
Nater
Urs M
UM
Reeves
William C
WC
D000293:Adolescent; D000328:Adult; D052636:Allostasis / Q000502:physiology*; D015992:Body Mass Index; D016022:Case-Control Studies; D003866:Depressive Disorder; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D005260:Female; D005845:Georgia / Q000453:epidemiology; D006304:Health Status; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D012307:Risk Factors; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014505:Urban Population