A study was conducted on the relationship between cardiac mortality and unlucky days among Chinese- and Japanese-Americans and white Americans. In December issue of the British Medical Journal, the study findings were published in an article, "The Hound of the Baskervilles effect: natural experiment on the influence of psychological stress on timing of death," by David Phillips and others. In The Hound of the Baskervilles, Berskerville died from heart attack induced by stress.
The study examined death certificates of Americans between January 1973 and December 1998. According to the authors, in Mandarin, Cantonese, and Japanese, the words "death" and "four"are pronounced almost identically. Some Chinese and Japanese hospitals do not list a fourth floor and number 4 for any room. Mainland Chinese omit the number 4 in designating military aircrafts. The number 4 was considered unlucky by Chinese and Japanese people.
On the fourth of the month, cardiac deaths were significantly more frequent than on any other date of the month, a 7% higher than the average for t rent of the week. Their findings concludes that excess cardiac morality on "unlucky" days consistent with the hypothesis that cardiac mortality increases on psychologically stressful occasions.