Seasonal birth patterns in myositis subgroups suggest an etiologic role of early environmental exposures - PubMed (original) (raw)

Seasonal birth patterns in myositis subgroups suggest an etiologic role of early environmental exposures

Leora J Vegosen et al. Arthritis Rheum. 2007 Aug.

Abstract

Objective: To evaluate whether seasonal early environmental exposures might influence later development of autoimmune disease, by assessing distributions of birth dates in groups of patients with idiopathic inflammatory myopathies (IIMs).

Methods: We assessed birth patterns in groups of patients with juvenile-onset IIM (n = 307) and controls (n = 3,942) who were born between 1970 and 1999, and in groups of patients with adult-onset IIM (n = 668) and controls (n = 6,991) who were born between 1903 and 1982. Birth dates were analyzed as circular data. Seasonal clustering was assessed by the Rayleigh test, and differences between groups by a rank-based uniform scores test.

Results: The overall birth distributions among patients with juvenile IIM and among patients with adult IIM did not differ significantly from those among juvenile and adult controls, respectively. Some subgroups of patients with juvenile IIM had seasonal birth distributions. Hispanic patients with juvenile-onset IIM had a seasonal birth pattern (mean birth date October 16) significantly different from that of Hispanic controls (P = 0.002), who had a uniform birth distribution, and from that of non-Hispanic patients with juvenile-onset IIM (P < 0.001), who had a mean birth date of May 2. Juvenile dermatomyositis patients with p155 autoantibody had a birth distribution that differed significantly from that of p155 antibody-negative juvenile dermatomyositis patients (P = 0.003). Juvenile IIM patients with the HLA risk factor allele DRB1*0301 had a birth distribution significantly different from those without the allele (P = 0.021). Similar results were observed for juvenile and adult IIM patients with the linked allele DQA1*0501, versus juvenile and adult IIM patients without DQA1*0501, respectively. No significant patterns in birth season were found in other subgroups.

Conclusion: Birth distributions appear to have stronger seasonality in juvenile than in adult IIM subgroups, suggesting greater influence of perinatal exposures on childhood-onset illness. Seasonal early-life exposures may influence the onset of some autoimmune diseases later in life.

PubMed Disclaimer

Figures

Figure 1

Figure 1. Hispanic juvenile idiopathic inflammatory myopathy (IIM) patients have a seasonal birth distribution that differs from non-Hispanic juvenile IIM patients and Hispanic controls

When birth dates are represented on a unit circle, the direction of the resultant is the angle that corresponds to the mean birth date. The mean resultant length, along with the sample size, is used in the Rayleigh test to assess the strength of seasonality against the null hypothesis of uniformity (14). The long resultant for the birth distribution for Hispanic juvenile IIM patients indicates strong seasonality, while the short resultant for the birth distribution for Hispanic controls indicates a birth distribution that is not significantly different from uniformity.

Figure 2

Figure 2

p155 autoantibody positive juvenile dermatomyositis patients differ in birth distribution from p155 autoantibody negative juvenile dermatomyositis patients.

Figure 3

Figure 3

HLA DRB1*0301 positive juvenile IIM patients differ in birth distribution from HLA DRB1*0301 negative juvenile IIM patients.

References

    1. Gillman MW. Developmental origins of health and disease. N Engl J Med. 2005;353:1848–1850. - PMC - PubMed
    1. Phillips DI. External influences on the fetus and their long-term consequences. Lupus. 2006;15(11):794–800. - PubMed
    1. Gazala E, Ron-Feldman V, Alterman M, Kama S, Novack L. The association between birth season and future development of childhood asthma. Pediatr Pulmonol. 2006;41(12):1125–1128. - PubMed
    1. Dauvilliers Y, Carlander B, Molinari N, Desautels A, Okun M, Tafti M, et al. Month of birth as a risk factor for narcolepsy. Sleep. 2003;26(6):663–665. - PubMed
    1. Jones AL, Mowry BJ, Pender MP, Greer JM. Immune dysregulation and self-reactivity in schizophrenia: do some cases of schizophrenia have an autoimmune basis? Immunol Cell Biol. 2005;83(1):9–17. - PubMed

Publication types

MeSH terms

LinkOut - more resources