Subclinical Thyroid Dysfunction and Frailty Among Older Men.
BACKGROUND
Both subclinical thyroid dysfunction and frailty are common among older individuals, but data on the relationship between these 2 conditions are conflicting.


OBJECTIVE
The purpose of this study was to assess the cross-sectional and prospective associations between subclinical thyroid dysfunction and frailty and the 5 frailty subdomains (sarcopenia, weakness, slowness, exhaustion, and low activity).


METHODS
The Osteoporotic Fractures in Men Study is a prospective cohort study.


METHODS
Men older than 65 years (n = 1455) were classified into 3 groups of thyroid status: subclinical hyperthyroidism (n = 26, 1.8%), subclinical hypothyroidism (n = 102, 7.0%), and euthyroidism (n = 1327, 91.2%).


METHODS
Frailty was defined using a slightly modified Cardiovascular Health Study Index: men with 3 or more criteria were considered frail, men with 1 to 2 criteria were considered intermediately frail, and men with no criteria were considered robust. We assessed the cross-sectional relationship between baseline thyroid function and the 3 categories of frailty status (robust/intermediate/frail) as well as the prospective association between baseline thyroid function and subsequent frailty status and mortality after a 5-year follow-up.


RESULTS
At baseline, compared with euthyroid participants, men with subclinical hyperthyroidism had an increased likelihood of greater frailty status (adjusted odds ratio, 2.48; 95% confidence interval, 1.15-5.34), particularly among men aged <74 years at baseline (odds ratio for frailty, 3.63; 95% confidence interval, 1.21-10.88). After 5 years of follow-up, baseline subclinical hypothyroidism and hyperthyroidism were not consistently associated with overall frailty status or frailty components.


CONCLUSIONS
Among community-dwelling older men, subclinical hyperthyroidism, but not subclinical hypothyroidism, is associated with increased odds of prevalent but not incident frailty.
Department of Internal Medicine (V.S.V.), University Hospital of Zürich, 8091 Zürich, Switzerland; Department of General Internal Medicine (N.R.), Inselspital, University Hospital of Bern, 3010 Bern, Switzerland; California Pacific Medical Center Research Institute (L.H.), San Francisco, California 94107; Stanford University Medical School (A.R.H.), Palo Alto, California 94305; Bone and Mineral Unit (E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Department of Medicine (K.E.E.) and Division of Epidemiology and Community Health (K.E.E.), University of Minnesota, Minneapolis, Minnesota 55455; Center for Chronic Disease Outcomes Research (K.E.E.), Minneapolis Veterans Affairs Health Care System, Minneapolis, Minnesota 55417; and Departments of Medicine and Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California 94143.
Vanessa S
VS
Virgini
Department of Internal Medicine (V.S.V.), University Hospital of Zürich, 8091 Zürich, Switzerland; Department of General Internal Medicine (N.R.), Inselspital, University Hospital of Bern, 3010 Bern, Switzerland; California Pacific Medical Center Research Institute (L.H.), San Francisco, California 94107; Stanford University Medical School (A.R.H.), Palo Alto, California 94305; Bone and Mineral Unit (E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Department of Medicine (K.E.E.) and Division of Epidemiology and Community Health (K.E.E.), University of Minnesota, Minneapolis, Minnesota 55455; Center for Chronic Disease Outcomes Research (K.E.E.), Minneapolis Veterans Affairs Health Care System, Minneapolis, Minnesota 55417; and Departments of Medicine and Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California 94143.
Nicolas
N
Rodondi
Department of Internal Medicine (V.S.V.), University Hospital of Zürich, 8091 Zürich, Switzerland; Department of General Internal Medicine (N.R.), Inselspital, University Hospital of Bern, 3010 Bern, Switzerland; California Pacific Medical Center Research Institute (L.H.), San Francisco, California 94107; Stanford University Medical School (A.R.H.), Palo Alto, California 94305; Bone and Mineral Unit (E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Department of Medicine (K.E.E.) and Division of Epidemiology and Community Health (K.E.E.), University of Minnesota, Minneapolis, Minnesota 55455; Center for Chronic Disease Outcomes Research (K.E.E.), Minneapolis Veterans Affairs Health Care System, Minneapolis, Minnesota 55417; and Departments of Medicine and Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California 94143.
Peggy M
PM
Cawthon
Department of Internal Medicine (V.S.V.), University Hospital of Zürich, 8091 Zürich, Switzerland; Department of General Internal Medicine (N.R.), Inselspital, University Hospital of Bern, 3010 Bern, Switzerland; California Pacific Medical Center Research Institute (L.H.), San Francisco, California 94107; Stanford University Medical School (A.R.H.), Palo Alto, California 94305; Bone and Mineral Unit (E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Department of Medicine (K.E.E.) and Division of Epidemiology and Community Health (K.E.E.), University of Minnesota, Minneapolis, Minnesota 55455; Center for Chronic Disease Outcomes Research (K.E.E.), Minneapolis Veterans Affairs Health Care System, Minneapolis, Minnesota 55417; and Departments of Medicine and Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California 94143.
Stephanie Litwack
SL
Harrison
Department of Internal Medicine (V.S.V.), University Hospital of Zürich, 8091 Zürich, Switzerland; Department of General Internal Medicine (N.R.), Inselspital, University Hospital of Bern, 3010 Bern, Switzerland; California Pacific Medical Center Research Institute (L.H.), San Francisco, California 94107; Stanford University Medical School (A.R.H.), Palo Alto, California 94305; Bone and Mineral Unit (E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Department of Medicine (K.E.E.) and Division of Epidemiology and Community Health (K.E.E.), University of Minnesota, Minneapolis, Minnesota 55455; Center for Chronic Disease Outcomes Research (K.E.E.), Minneapolis Veterans Affairs Health Care System, Minneapolis, Minnesota 55417; and Departments of Medicine and Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California 94143.
Andrew R
AR
Hoffman
Department of Internal Medicine (V.S.V.), University Hospital of Zürich, 8091 Zürich, Switzerland; Department of General Internal Medicine (N.R.), Inselspital, University Hospital of Bern, 3010 Bern, Switzerland; California Pacific Medical Center Research Institute (L.H.), San Francisco, California 94107; Stanford University Medical School (A.R.H.), Palo Alto, California 94305; Bone and Mineral Unit (E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Department of Medicine (K.E.E.) and Division of Epidemiology and Community Health (K.E.E.), University of Minnesota, Minneapolis, Minnesota 55455; Center for Chronic Disease Outcomes Research (K.E.E.), Minneapolis Veterans Affairs Health Care System, Minneapolis, Minnesota 55417; and Departments of Medicine and Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California 94143.
Eric S
ES
Orwoll
Department of Internal Medicine (V.S.V.), University Hospital of Zürich, 8091 Zürich, Switzerland; Department of General Internal Medicine (N.R.), Inselspital, University Hospital of Bern, 3010 Bern, Switzerland; California Pacific Medical Center Research Institute (L.H.), San Francisco, California 94107; Stanford University Medical School (A.R.H.), Palo Alto, California 94305; Bone and Mineral Unit (E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Department of Medicine (K.E.E.) and Division of Epidemiology and Community Health (K.E.E.), University of Minnesota, Minneapolis, Minnesota 55455; Center for Chronic Disease Outcomes Research (K.E.E.), Minneapolis Veterans Affairs Health Care System, Minneapolis, Minnesota 55417; and Departments of Medicine and Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California 94143.
Kristine E
KE
Ensrud
Department of Internal Medicine (V.S.V.), University Hospital of Zürich, 8091 Zürich, Switzerland; Department of General Internal Medicine (N.R.), Inselspital, University Hospital of Bern, 3010 Bern, Switzerland; California Pacific Medical Center Research Institute (L.H.), San Francisco, California 94107; Stanford University Medical School (A.R.H.), Palo Alto, California 94305; Bone and Mineral Unit (E.S.O.), Oregon Health & Science University, Portland, Oregon 97239; Department of Medicine (K.E.E.) and Division of Epidemiology and Community Health (K.E.E.), University of Minnesota, Minneapolis, Minnesota 55455; Center for Chronic Disease Outcomes Research (K.E.E.), Minneapolis Veterans Affairs Health Care System, Minneapolis, Minnesota 55417; and Departments of Medicine and Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California 94143.
Douglas C
DC
Bauer
D000368:Aged; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005500:Follow-Up Studies; D016330:Frail Elderly; D006801:Humans; D006980:Hyperthyroidism / Q000150:complications; D007037:Hypothyroidism / Q000150:complications; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D018908:Muscle Weakness / Q000453:epidemiology / Q000209:etiology; D015995:Prevalence; D011446:Prospective Studies; D055948:Sarcopenia / Q000453:epidemiology / Q000209:etiology; D012959:Socioeconomic Factors; D013959:Thyroid Diseases / Q000150:complications* / Q000453:epidemiology; D013960:Thyroid Function Tests