Descriptive epidemiology of lipomyelomeningocele, Hawaii, 1986-2001
Mathias B Forrester1, Ruth D Merz
1Hawaii Birth Defects Program, Honolulu, HI 96817, USA.
Background:
The epidemiology of neural tube defects (NTDs) may depend on the type of the defect and its location. There is little epidemiologic information on lipomyelomeningocele, a type of NTD. The objective of this investigation was to describe the epidemiology of lipomyelomeningocele.
Methods:
Cases were obtained from a Hawaii birth defect registry and consisted of all infants delivered during 1986-2001 with lipomyelomeningocele. Lipomyelomeningocele rates per 10,000 births were calculated for various factors.
Results:
A total of 17 cases of lipomyelomeningocele were identified, for a total rate of 0.57. When the lipomyelomeningocele rate was examined with respect to the time period of folic acid fortification of cereal grains in the United States, the rate was 0.57 during 1986-1996 (prefortification), 0.57 during 1997-1998 (voluntary fortification), and 0.58 during 1999-2001 (mandatory fortification). A total of 11 (64.7%) of the cases were female. Lipomyelomeningocele rates were higher among infants born to mothers in younger and older age groups. The rate was highest among Pacific Islanders, followed by Filipinos and Far East Asians, and lowest among whites. Rates were greater with lower birth weight and gestational age and among multiple births.
Conclusions:
Lipomyelomeningocele rates were not found to be affected by folic acid fortification. The majority of cases were female. Other demographic and clinical factors appear to be associated with lipomyelomeningocele risk. None of the differences in rates between the various subgroups were statistically significant, and due to the small number of cases, the 95% confidence interval (CI) ranges were wide. However, the findings suggest possible patterns of occurrence. Additional studies involving larger numbers of cases are recommended.
