Association between androgenetic alopecia and coronary artery disease in young male patients.

BACKGROUND: Several studies have demonstrated an association between androgenetic alopecia (AGA) and cardiovascular disease. Still controversies exist regarding the association. Are they truly associated?
OBJECTIVE: The purpose of the present study was to assess the prevalence of AGA and establish its association in young (<45 years) Asian Indian Gujarati male patients having coronary artery disease (CAD).
MATERIALS AND METHODS: Case-control prospective multicentric study was carried out on 424 men. Case group consisted of 212 male subjects having CAD (Group 1) and another 212, either sibling or first degree male relative of the case subjects (having no evidence of CAD) were considered as the control group (Group 2). Age, total cholesterol, incidence of diabetes mellitus, and hypertension were similar in both groups. The degree of alopecia was assessed using the Norwood-Hamilton scale for men. Statistical analysis was performed using Chi-square test.
RESULTS: AGA was found in 80 (37.73%) young CAD patients (Group 1), whereas 44 (20.7%) of patients had alopecia in the control group (Group 2). There was statistically significant association between male AGA and CAD (P = 0.001). Odds ratio was 2.70 (95% confidence interval [CI], 1.72 ± 4.26). Statistically significant association was found between high grade baldness (Grades IV-VII) and CAD in young men (P < 0.05). Odds ratio = 2.36 (95% CI, 1.108 ± 5.033). There is statistically significant association of AGA in young Asian Gujarati male with CAD and the prevalence of AGA in young CAD patient is 37.73%.
CONCLUSION: This study implies early onset AGA in male is independently associated with CAD, though mechanisms need to be investigated.

INTRODUCTION

Androgenetic alopecia (AGA) has been associated with ischemic heart disease (IHD).[1234] These are statistically significant, though weak associations ascertained by previously done epidemiological, cohort and case-control studies.[5] Male pattern baldness (MPB) may be the risk factor for cardiovascular disease was first suggested, in 1972, when Cotton et al. indicated an association between cardiovascular diseases and hair loss.[6] No clear mechanistic relation between these could be discovered.[78] High androgen level has been postulated that lead to both AGA and atherosclerosis and thrombosis.[9] Male AGA is inherited as a complex polygenic trait. It has been demonstrated that severe early onset of AGA in young subject (<30 years) have an increased risk of IHD.[2] A study showed that men with higher grades of AGA (vertex), have a higher risk of developing IHD, especially among men having high cholesterol level and hypertension.[3] However, there are discrepancies in regards to the nature of this relationship. Some indicated that the rate of progression, rather than the presence or degree of baldness, was important.[10] Others suggested that the pattern of baldness was relevant, but disagreed on the relative importance of frontal baldness[3] versus vertex baldness.[24] The purpose of the present study was to assess the prevalence of AGA and establish its association in young (<45 years) Asian Indian Guajarati male patients having coronary artery disease (CAD).

MATERIALS AND METHODS

Recruitment and data collection

To carry out case-control prospective multicentric study a total of 424 young men aged <45 years belonging to Guajarati Indian community were studied for AGA pattern based on Hamilton-Norwood scale from U.N Mehta Institute of Cardiology and Research and Life care Hospital, Ahmedabad, Gujarat, India during the period of year 2007-2010 [Table 1].

Table 1

Distribution of pattern of AGA among subjects

Subjects (cases) were defined as patients with proven CAD either with history or current presentation of acute coronary syndrome (non-ST-segment elevation myocardial infarction or ST-segment elevation myocardial infarction) or angiographically proven CAD (n = 212). Sibling (brother) or first degree male relatives of the case subjects, without any evidence of CAD (no history of CAD and with normal electrocardiogram and echography findings) (n = 212) were evaluated for AGA as control population. Population had similar incidence of hypertension/diabetes mellitus/total cholesterol/age [Table 2]. The diagnosis of male AGA was made on the basis of detailed history and clinical examination. Subjects were classified according to Hamilton-Norwood scale for grading of AGA in males (Grades I-VII).[11] Further, subjects with AGA Grades I-III were considered having low grade AGA and those with AGA Grades IV-VII were regarded to be having high grade AGA.

Table 2

Clinical and laboratory characters of study groups

Statistical analysis

Two tailed test were used. Chi-square test is used as a test for significance for bivariate associations and comparisons. P < 0.05 was considered to be an evidence for statistical significance. We also calculated standard error of difference between two proportions. The significance of difference is found by normal deviate, Z-test.

RESULT

Androgenetic alopecia was found in 80 (37.73%) of patients in young CAD patients, whereas 44 (20.7%) of patients had alopecia in the control group. There was statistically significant association between male AGA and CAD (P = 0.001). Odds ratio was 2.70 (95% confidence interval [CI], 1.72 ± 4.26) [Table 3]. Statistically significant association was found between high grade baldness (Grades IV-VII) and CAD in young men (P < 0.05) [Table 4]. Odds ratio = 2.36 (95% CI, 1.108 ± 5.033).

Table 3

Statistically significant association between male AGA and CAD

Table 4

Statistically significant association between young male high grade AGA (Grades IV-VII) and CAD

DISCUSSION

Epidemiological studies examining MPB and coronary heart disease (CHD) have tended to support a positive association.[2346121314] A plausible explanation for an association between baldness and CHD may be elevated androgen levels.[151617] Men with severe baldness seem to have a greater number of androgen receptors in the scalp[18] and higher levels of both serum total and free testosterone.[19] One alternative possible link between MPB and CHD could be a similar pattern of inheritance, as others have speculated.[20] In our study, we have got statistically significant association of AGA in young Asian Gujarati male with CAD and the incidence of AGA in young (<45 years) CAD patient is 37.73%. And also significant association has been found between vertex baldness (Grades IV-VII) and CAD in young male population. Although early vertex baldness may be a nonmodifiable risk factor for CHD, it may serve as a useful clinical marker to identify men at increased risk, who may benefit from aggressive screening and primary prevention efforts directed toward other known modifiable risk factors for CHD.

CONCLUSION

In summary, however, our study provides support for the hypothesis that vertex pattern baldness is a marker for increased risk of CHD events. Further research is needed to corroborate these findings and to clarify the biological mechanisms that may explain this relationship.