When do people normally develop grey hair?
Typically, Caucasians begin greying in their mid-30s; Asians in the late 30s; African-Americans in the mid-40s. About one half of the world's population has some degree of greying by age 50. The term "premature greying" refers to hair greying that occurs before the age of 20-25 in Caucasians and before 30 in black men and women.
Causes of grey hair
I occassionally evaluate patients in my clinic who start greying in the teens or twenties. Many, many factors influence hair greying especially genetics. Thyroid abnormalities, pituitary problems, B12 deficiency are just three examples of many conditions that cause early greying. Smoking too can cause early greying. In fact, a 1996 study in the British Medical Journal showed that smokers are about two to four times more likely to have grey hair. A recent study supports a possible link between low iron, calcium and vitamin D but that needs to be further investigated.Autoimmune conditions like alopecia areata, vitiligo and premature aging syndromes (like a condition called Werner's) can cause early greying of hair. High stress levels may cause greying in animal models but it's not yet clear if stress contributes to greying in humans.
Overall, early greying of hair is fairly common and not usually associated with any underlying problem. That said, a full workup is needed for greying that fits the definition of premature greying. Evaluation of cardiovascular risk factors is also important in such situations.
REFERENCES FOR FURTHER READING
Kocaman SA, et al. The degree of premature hair graying as an independent risk marker for coronary artery disease: a predictor of biological age rather than chronological age. Anadolu Kardiyol Derg. 2012.
Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Vancouver office at 604.283.9299