Prevalence of alopecia areata

differs by race in two large cohorts

Jordan M. Thompson, BS, MSIV, Min Kyung Park, PhD,

Tricia Li, MS, Abrar A. Qureshi, MD, MPH, and

Eunyoung Cho, ScD

Epidemiology of AA

• Focus on: medical and psychiatric comorbidities

– E.g. thyroid disease, depression/anxiety

• National Alopecia Areata Registry; phenomenal

resource

• Few large population based studies

Epidemiology of AA

• 2 population based studies1,2; Olmstead

County, Minnesota

• Rochester Epidemiology Project

• Cumulative lifetime incidence of 1.7-

2.1%

• Racial homogeneity of region

precludes comparisons of relative

incidence/prevalence by race

1Mirzoyev SA, Schrum AG, Davis MD, Torgerson RR. Lifetime incidence risk of alopecia areata estimated at 2.1% by Rochester

Epidemiology Project, 1990-2009. J Invest Dermatol. 2014 Apr;134(4):1141-2.2Safavi KH, Muller SA, Suman VJ, Moshell AN, Melton LJ 3rd. Incidence of alopecia areata in Olmsted County, Minnesota, 1975

through 1989. Mayo Clin Proc. 1995 Jul;70(7):628-33.

Our question

• Does the risk of AA differ by self-

reported race?

Methods

• Nurses’ Health Study

– Est. 1976; goal: long-term consequences of oral

contraceptives

– 121,700 female nurses (30-55 y/o) answered baseline

questionnaire re: lifestyle factors and medical history

– 11 most populous states with Nursing Boards that agreed to

release address data

• California, Connecticut, Florida, Maryland, Massachusetts,

Michigan, New Jersey, New York, Ohio, Pennsylvania, and Texas

– Follow-up questionnaires every 2 years since

– Response rate >90% in most 2 year cycles

Methods

• Nurses’ Health Study II

– Est. 1989; 116,430 female nurses (25-42 y/o, compared to

30-55 y/o in NHS) answered baseline questionnaire re:

lifestyle factors and medical history

– 11 most populous states with nursing Boards that agreed to

release address data

• California, Connecticut, Indiana, Iowa, Kentucky, Massachusetts,

Michigan, Missouri, New York, North Carolina, Ohio, Pennsylvania,

South Carolina, and Texas

– Follow-up questionnaires every 2 years since

– Response rate 85-90% in most 2 year cycles

Methods

NHS 2012

NHS II 2011NHS II 1985 and 2005

NHS 1992 and 2004

Race Alopecia areata history

Methods

• Logistic regression analysis to determine odds ratios

(OR) for diagnosis of alopecia areata comparing

black- to white-identifying respondents

– Age-adjusted model

– Multivariate model adjusting for:• age, smoking status, alcohol intake, body mass index, physical activity, UV-B flux at

residence, post-menopausal hormone use, and history of immune-mediated disease

(e.g. psoriasis, systemic lupus), cardiovascular disease, hypertension, high

cholesterol, or diabetes

Results

Cohort Race Total Participants # of AA

Cases

% Lifetime

Prevalence

Age-adjusted Odds Ratios

(95%CI)

Multivariate-adjusted

Odds Ratios (95%CI)

NHS White 55562 358 0.64 1 (referent) 1 (referent)

Black 702 9 1.28 2.01 (1.04-3.92) 2.16 (1.10-4.23)

NHS2 White 90408 712 0.79 1 (referent) 1 (referent)

Black 1476 61 4.13 5.29 (4.05-6.91) 5.17 (3.54-7.55)

Table 1. Alopecia areata percent prevalence and odds ratios by race in cross-sectional analyses of

the Nurses Health Study (NHS) and Nurses Health Study 2 (NHS2)

Past evidence?

• National Ambulatory

Medical Care Survey

• ICD-9 codes to

identify AA visits

Discussion

• Explanation 1: There is a true disparity in burden of

disease between black- and white- identifying women

– 1. Some aspect of AA pathophysiology that predisposes

black women?

• Autoimmune predisposition? E.g. Lupus is 3x as common in black

women

• Genetic predisposition

Discussion

• Explanation 2: Black female respondents might

endorse history of AA, but in fact had a different type

of hair loss, itself more prevalent in black women

Traction alopecia Central centrifugal cicatricial

alopecia (CCCA)

Conclusions

• Nurses’ Health Study Cohorts; 1165 total AA cases

– Rich lifestyle factor data over decades: e.g. diet, exercise, medication

use

• Present study: Self-reported, Dr. Dx’d AA is more common

in black women in NHS I and II

– Disparity may be true

– or is explained by greater prevalence of other hair loss conditions

(CCCA, traction alopecia)

• Findings draw attention to diagnostic challenge in hair loss

• Important consideration for epidemiologic studies of AA

Future Directions

• Two ways to validate these self-reported

AA dx

– Medical record review

– Secondary screening questionnaire• Collaboration with Dr. Arash Mostaghimi and Dr. Kathy Huang

(Harvard)

• Pilot testing ongoing

Thank you!

• Nurses’ Health Study I/II participants

• Mentors:

– Abrar Qureshi, MD, MPH

– Eunyoung Cho, ScD

• Colleagues: Min Kyung Park, PhD, Tricia Li, MS