Final answer:
Diagonal folds in the ear lobe have been correlated with an increased risk of heart disease, which is an interesting finding given that the external ear structures are not functionally related to the heart.
Step-by-step explanation:
Diagonal folds in the skin of the ear lobe have been correlated with heart disease. These external ear structures, including the auricle and the ear canal up to the tympanic membrane, are not directly associated with heart function, yet observational studies have found a link between ear lobe creases and an increased risk of heart disease. However, it is important to note that while such a correlation exists in epidemiological studies, ear crease is not a diagnostic tool and further medical evaluation is necessary for a heart disease diagnosis.