Summary of evidence
This study investigated if there is a significant association between
the presence of a diagonal ear lobe crease (DELC) and coronary artery
disease (CAD) independent of age. By using the gold standard diagnosis
for CAD, angiography, we were able to provide a more objective analysis
than other reviews which have included autopsy studies and clinically
diagnosed heart disease(3). Our study found that
patients with DELC have an increased likelihood of having CAD. Also
despite some previous studies suggesting that DELC was simply a result
of age, all ten of the included studies that looked at this found that
the relationship between DELC and CAD was independent of age and all
other conventional cardiovascular risk factors.
We also looked to see if the diagnostic odds ratio varied between
different cohorts. In looking at different age groups, only one
study(6) provided their findings for each age bracket
and although it found that the diagnostic odds ratio was greatest in the
youngest cohort, the population size of each cohort was relatively small
and it is difficult to assess the validity of this finding without other
studies. Similarly, only one study looked at different odds ratio
between genders and found that it was greater in women than men (OR
6.368 vs 5.420) however it is difficult to assess this effect overall in
our analysis as there was frequently a disparate gender ratio between
the case and control groups. Whilst this is due to poor recruitment, it
may partly be influenced by there being a reduced prevalence of CAD in
women and also some studies excluding patients with ear lobe piercings
causing an iatrogenic DELC. Other studies(20) have
found no difference in the prevalence of DELC between males and females.
As the included studies spanned eight different countries it is believed
that the results are applicable to multiple ethnic populations. However
it is difficult to determine the impact of ethnicity especially as there
are few studies which look at the general prevalence of DELC in a
healthy population. Without knowing the generalised prevalence of DELC
and relationship with CAD in different populations it is difficult to
ascertain the impact of ethnicity.
Although this study found that patients with DELC have an increased
likelihood of having CAD, there was wide variance in the sensitivity and
specificity of DELC as a diagnostic test. This supports findings from
other studies that indicate DELC should only be used as a physical
marker not a diagnostic clinical test for CAD(12).