Potential need for race-specific diagnostic criteria and healthcare delivery for thyroid hormone abnormalities Yutaka Aoki Morgan State University School of Community Health and Policy October 21, 2010 Seventh National Conference on Quality Health Care for Culturally Diverse Populations

Thyroid health racial disparities Yutaka Aoki 2 Racial disparities & SES: Brief Overview Race represents many factors Minority race/ethnicity often associated w/ –Lower income –Lower education –Etc. These correlates often termed collectively as socioeconomic status (SES)

Thyroid health racial disparities Yutaka Aoki 3 SES as basis for Racial Disparities in Health SES is often mediator in many racial disparities –E.g., in asthma, cardiovascular disease, etc. –Minority race  Low SES (common in minority)  Limited access to high-quality healthcare  More/severe disease Other mediators –Unhealthy life style? –Stress/discrimination? –Limited access to grocery (fresh fruits & vegetables)? –Others

Thyroid health racial disparities Yutaka Aoki 4 Known racial difference with genetic basis Some racial difference has biological/genetic bases, e.g.: –Sickle Cell Disease more common in African Americans (AAs) Genetics non-modifiable unlike: Unhealthy life style—may be modified through behavioral intervention Discrimination—may be modified through societal changes

Thyroid health racial disparities Yutaka Aoki 5 Biology/Generics or SES? Often answer is not “one or the other” Could be intertwined –E.g., in breast cancer

Thyroid health racial disparities Yutaka Aoki 6 Intertwined Relationship: Breast Cancer in Case Lower incidence & higher mortality in AAs Thought as access-to-care issue –Mammography in last 2 years: 63% in blacks vs. 67% in whites (Chagpar et al, 2008, Surgery) Has turned out breast cancer of black women tend to be more fatal type –i.e., different breast cancer in minority (Dunn et al., 2010, Breast Cancer Res Treat)

Thyroid health racial disparities Yutaka Aoki 7 Disease itself, not just risk for same disease, may vary across races Different manifestations—signs and symptoms Different description of same symptoms by patients Distribution of disease biomarkers among individuals with or without disease –Focus of this presentation

Thyroid health racial disparities Yutaka Aoki 8 Case in point: Thyroid hormone abnormalities Different profile of thyroid health for non- Hispanic whites, blacks, and Hispanics (Aoki et al., 2007, Thyroid) Does difference arise from: –Biological difference? –Access to care/SES? This presentation deals with: –Unanswered questions –Implications

Thyroid health racial disparities Yutaka Aoki 9 Thyroid hormone basics: Signs and symptoms Hypothyroidism—too little thyroid hormone –Signs and symptoms decreased metabolism –Weight gain, sluggishness/tiredness, depression, slow heart beats, etc. Hyperthyroidism—too much thyroid hormone –Symptoms and signs of increased metabolism –Weight loss, bone loss, restlessness, rapid heart beats, high appetite, etc.

Thyroid health racial disparities Yutaka Aoki 10 Thyroid hormone basics: Diagnosis Measure serum T4 (thyroxine) –Low T4—hypothyroidism –High T4—hyperthyroidism Serum TSH (thyroid stimulating hormone) actually used more often for dx, though –High TSH—hypothyroidism –Low TSH—hyperthyroidism Note flip in high/low –T4 and TSH negatively associated –People with high T4 tend to have low TSH, vice versa

Thyroid health racial disparities Yutaka Aoki 11 African American (AA)-white difference in thyroid health AAs have: –Higher total T4, lower TSH than whites –Lower hypothyroidism prevalence –Higher hyperthyroidism prevalence (Aoki et al., 2007, Thyroid) Biological basis—Caucasians adapted to colder climate in Europe (vs. Africa) Is “access to care” a factor? –Largely unanswered (but probably not so)

Thyroid health racial disparities Yutaka Aoki 12 Thyroid hormone abnormality’s long-term consequences Hypothyroidism can cause/associated with: –CVD (Ochs et al., 2008, Ann Intern Med) Treatment for hypothyroidism associated with: –More hospitalizations, greater use of non-thyroid prescription medications (Aoki, unpublished) Hyperthyroidism can cause/associated with: –CVD (Ochs et al., 2008, Ann Intern Med) –Osteoporosis (Biondi et al., 2005, Eur J Endocrinol)

Thyroid health racial disparities Yutaka Aoki 13 Higher CVD mortality/morbidity for blacks Thyroid health difference may play some (small) roles Probably small roles because hypo/hyperthyroidism is not common: –Hypothyroid blacks may be undertreated with current universal tx goal, yet blacks have relatively low hypothyroidism prevalence –Hyperthyroidism, which is more common in blacks, still is relatively rare (prevalence ≈ 1%)

Thyroid health racial disparities Yutaka Aoki 14 Universal (non race-specific) cut-offs used for most studies Cut-offs has been in use for decades (with revisions) Apparently earlier clinical studies conducted in majority Caucasians

Thyroid health racial disparities Yutaka Aoki 15 “Universal” cut-offs for hyperthyroidism appropriate? Suppose a black patient has TSH = 0.08 mIU/L (i.e., slightly below universal cut-off of 0.08 mIU/L for hyperthyroidism) Standard interpretation and action Slightly below cut-off equally bad for blacks and whites Treat accordingly

Thyroid health racial disparities Yutaka Aoki 16 “Universal” cut-offs for hyperthyroidism appropriate? (cont’d) Suppose a black patient has TSH = 0.08 mIU/L (i.e., slightly below universal cut-off of 0.08 mIU/L for hyperthyroidism) Alternative interpretation and action TSH = 0.08 mIU/L may be OK for blacks, if blacks “naturally” tend to have lower TSH (and higher T4, i.e., be on hyperthyroid side) Don’t treat

Thyroid health racial disparities Yutaka Aoki 17 “Universal” cut-offs for hypothyroidism appropriate? When treating hypothyroid black patients: –Should we try to lower TSH in range between mIU/L (as currently recommended irrespective of race in NACB, 2002)? or –Should we try to set a lower range for TSH for blacks? (recall blacks “naturally” have lower TSH and higher T4)

Thyroid health racial disparities Yutaka Aoki 18 Potential healthcare implications for genetic racial difference 1.Race-specific diagnostic criteria 2.Race-specific treatment regimen 3.Culturally-sensitive strategies for patient education Research on #1 and #2 missing to date

Thyroid health racial disparities Yutaka Aoki 19 Clinical knowledge gaps Do we need race-specific diagnostic criteria for thyroid hormone abnormalities? Do we need race-specific treatment goals for thyroid hormone abnormalities?

Thyroid health racial disparities Yutaka Aoki 20 How to fill “clinical knowledge gap”? Determine whether hypothyroidism symptoms increases with decrease in T4 in a similar manner for blacks and whites Determine whether hyperthyroidism symptoms increases with increase in T4 in a similar manner for blacks and whites Determine whether hypo/hyperthyroidism treatments work similarly for blacks and whites (can use same Tx goals?)

Thyroid health racial disparities Yutaka Aoki 21 Challenges in research on symptoms Symptoms could be (reported) differently by racial groups! –E.g., for major depression (Uebelacker et al., 2009, Psychol Med) “Tolerable” levels may vary by race –Physiological –Cultural Translation issues in healthcare setting (questionnaire/interview)

Thyroid health racial disparities Yutaka Aoki 22 Alternative to symptoms as outcome to study Use other clinical (“hard”) outcome, e.g., CVD or osteoporosis, rather than hypo/hyperthyroidism signs and symptoms, e.g.: –CVD –Total mortality –Osteoporosis –QOL

Thyroid health racial disparities Yutaka Aoki 23 Alternative research strategies Determine whether risk of CVD and other consequence of hypo/hyperthyroidism increases with decrease in thyroxine in a similar manner for blacks and whites Determine whether hypo/hyperthyroidism Tx works similarly for blacks and whites in CVD prevention Both addresses race as effect modifier

Thyroid health racial disparities Yutaka Aoki 24 Implication for race-specific dx criteria or tx goal Doctor/Nurse: We will treat you (black patient) differently from white patient. Potentially objectionable/confusing message Message need to be delivered culturally- sensitive, politically-correct manner

Thyroid health racial disparities Yutaka Aoki 25 Related debate: Need age-specific cut-offs for thyroid hormones? There is age-related change in distribution of thyroid hormone levels –As people age: T4 lowers & TSH rises More spread for both Ongoing debate: –Should we have separate cut-offs for elderly? Yes. (Surks &Hollowell, 2007, J Clin Endocrinol Metab)

Thyroid health racial disparities Yutaka Aoki 26 Summary Race-specific diagnostic criteria and treatment regimen may be needed for thyroid hormone abnormalities If the need proven, careful delivery of messages needs to be developed