Incidence of acquired CNS demyelinating syndromes in a multiethnic cohort of children

Abstract

Objective: To determine whether the incidence and clinical features of pediatric multiple sclerosis (MS) and other forms of pediatric acquired demyelinating syndromes (ADS) vary by race/ethnicity in a population-based cohort.

Methods: We used a combination of electronic database searches followed by complete medical records review to identify all children diagnosed with MS and ADS in the multiethnic membership of Kaiser Permanente Southern California from January 1, 2004, to December 31, 2009. Incidence rates were standardized to the US census by age and gender.

Results: We identified 81 incident cases of ADS from 4.87 million person-years of observation in children 0-18 years of age. The incidence rate of pediatric MS was 0.51 per 100,000 person-years (95% confidence interval [CI] 0.33-0.75) and incidence of other forms of ADS including optic neuritis, transverse myelitis, other forms of clinically isolated syndrome (CIS), and acute disseminated encephalomyelitis (ADEM) was 1.56 (95% CI 1.23-1.95) for an overall incidence of ADS of 1.66 per 100,000 person-years (95% CI 1.32-2.06). Incidence of ADS was higher in black (4.4 per 100,000 person-years, 95% CI 2.5-7.2, p < 0.001) and Asian/Pacific Islander (2.8, 95% CI 1.2-5.2, p = 0.02) than white (1.03, 95% CI 0.6-1.7) and Hispanic (1.5, 95% CI 1.1-2.1, per 100,000 person-years) children. Black children were also significantly more likely to have MS than white children (p = 0.001). Children who presented with ADEM were significantly younger than children with other types of ADS clinical presentations (mean age 5.6, range 0.7-17.6 years vs 14.6, range 2.7-18.5, respectively).

Conclusions: The incidence of pediatric acquired demyelinating syndromes is 1.66 per 100,000 person-years in a population-based cohort of Southern Californian children. The incidence of ADS and MS is higher in black children compared with white and Hispanic children.

Figure 1. Clinical phenotypes of acquired pediatric CNS demyelinating diseases vary with age

This diagram shows the relative distribution of clinical phenotypes in children with acquired demyelinating syndrome 12 years or younger compared with teenagers, 13 to 18 years of age. Acute disseminated encephalomyelitis (ADEM) (in gold) was rare among teenagers (n = 1) and multiple sclerosis (MS) (blue) was more common than in younger children. A female preponderance was present among teenagers but not younger children. CIS = clinically isolated syndrome; NMO = neuromyelitis optica; ON = optic neuritis; TM = transverse myelitis.

Figure 2. Incidence of pediatric multiple sclerosis (MS) and acquired demyelinating syndrome (ADS) is higher in black children

This graph shows incidence rates and 95% confidence intervals of pediatric MS (in blue), other forms of ADS (in gold), and all forms of ADS (in green). Black and Asian children have a significantly higher risk of pediatric ADS compared with white and Hispanic children (p < 0.001 and p = 0.02, respectively). Black children also have a significantly higher risk of pediatric MS compared with whites (p = 0.001). The sample size indicates the total number of children with ADS in each group.