Differences in Race and Ethnicity in Muscular Dystrophy Mortality Rates for Males under 40 Years of Age, 2006-2015

Abstract

Background/aims: Duchenne Muscular Dystrophy (DMD) has childhood onset, primarily affects males, and is usually fatal before the age of 40 years. Previous studies have indicated that this X-linked condition is more prevalent in whites than in blacks, but those were based on active surveillance, and limited to smaller populations and younger ages.

Methods: US death data were used to calculate mortality rates by race and ethnicity, with MD as either the underlying or multiple cause of death (MCD). Poisson approximation was used for confidence intervals; chi-square was used to compare rates.

Results: From 2006 to 2015, there were 3,256 deaths in males <40 years with MD as MCD, and 71% of these were aged 15-29 years. For whites, the average annual death rate was 0.43/100,000, which was significantly higher (p < 0.0001) that that of blacks (0.28), American Indian/Alaska Natives (0.20), and Asian/Pacific Islanders (0.21). The rate for non-Hispanic whites (0.46) was significantly higher (p < 0.0001) than the rates for Hispanic whites (0.31), Hispanic blacks (0.07), and non-Hispanic blacks (0.29).

Conclusion: Since DMD is the primary cause of deaths in young males with MD, mortality rates are a reasonable proxy for the relative difference in racial prevalence. It appears that DMD is significantly more common in white males than in males of other races.

Keywords: DBMD; Duchenne; Mortality rate; Muscular dystrophy; Racial differences.