The claim: smoking can cause hair loss
If an increased risk of respiratory illness, cancer and heart disease are not reason enough for many smokers to consider quitting, then perhaps a message focused on hair instead of health may do the trick. Scientists have long speculated cigarette smoke may accelerate hair loss and premature greying. The association was largely attributed to toxins in smoke that can harm hair follicles and damage hormones. According to epidemiological studies, that appears to be the case. A report in the journal ‘BMJ’ looked at more than 600 men and women, half of them smokers. After controlling for variables, the researchers found a “significant” and “consistent” link between smoking and early greying.
Last year, another team studied the link in a group of 740 men in Taiwan, aged 40 to 91, notable because Asian men generally have low rates of hereditary baldness. The researchers found a greater rate of hair loss among the smokers, a risk that grew with increased smoking.
The question that remains though is whether the link is a result of tobacco toxins directly affecting the scalp, or is it due to the diseases caused by smoking that speed up ageing.
The bottom line
Several studies suggest smoking can lead to premature greying and hair loss.
The claim: being left-handed adds to the risk of migraines
As if left-handers did not have it hard enough.
Already burdened with the minor mishaps that arise from living in a world designed for righties, their lot in life seemed to worsen considerably in the 1980s, when a study argued that southpaws had several times the risk of chronic headaches—and immune disorders—as their right-handed counterparts. The reason, it was theorized, had something to do with variations in foetal brain development, though no precise explanation was given.
But a raft of evidence now suggests that the migraine finding, though intriguing, was less fact than statistical artefact. A more extensive study published in March by German scientists examined a group of 100 patients who had received a diagnosis of migraine based on standards set by the International Headache Society. After finding no evidence of a link between handedness and migraines, the scientists pooled data from five other studies and conducted a meta-analysis. Still, there was no evidence of a relationship—a conclusion echoed by many similar studies. Several studies have also examined whether there is any relationship between left-handedness and increased risk of immune disorders. The findings are inconclusive. Proponents argue that foetal exposure to high levels of testosterone could be responsible, and they point out that left- handedness is more common in men. Critics say more research is needed.
The bottom line
Most studies have found that being left-handed does not increase the risk of migraines.
Anahad O’Connor/©2008/the New York Times