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Context and disease when disease risk is low: the case of type 1 diabetes in Sweden

Lynch, Kristian LU ; Subramanian, S. V.; Ohlsson, Henrik LU ; Chaix, Basile LU ; Lernmark, Åke LU and Merlo, Juan LU (2010) In Journal of Epidemiology and Community Health 64(9). p.789-795
Abstract
Background Several European studies have found significant small area variation in the risk of childhood onset (type 1) diabetes (T1D) which has been interpreted as evidence for contextual determinants of T1D. However, this conclusion may be fallacious since the limited number of newborn infants and the low risk for T1D is a source of spurious variability not properly handled by usual statistical methods. This study investigates the existence of contextual effects in the genesis of T1D, compares conclusions in previous reports with results obtained in a multilevel regression framework and highlights analysis of variance as a useful approach in public health. Methods All singletons born in Sweden between 1987 and 1991 were identified in the... (More)
Background Several European studies have found significant small area variation in the risk of childhood onset (type 1) diabetes (T1D) which has been interpreted as evidence for contextual determinants of T1D. However, this conclusion may be fallacious since the limited number of newborn infants and the low risk for T1D is a source of spurious variability not properly handled by usual statistical methods. This study investigates the existence of contextual effects in the genesis of T1D, compares conclusions in previous reports with results obtained in a multilevel regression framework and highlights analysis of variance as a useful approach in public health. Methods All singletons born in Sweden between 1987 and 1991 were identified in the Medical Birth Registry (n=560 766) and followed for diabetes until age 14 using the Hospital Discharge Registry. Area variation in the cumulative incidence of T1D was estimated by different statistical methods including multilevel logistic regression. Results The risk of T1D ranged from 4.3 to 6.5 per 1000 newborns across the counties (n=24) and from 0.0 to 19.2 per 1000 newborns across the municipalities (n=284). These differences were significant in standard statistical tests (counties, p=0.02; municipalities, p=0.007). However, according to multilevel analyses, the risk of T1D ranged from 4.7 to 5.7 and from 4.4 to 6.0 per 1000 newborns in counties and municipalities, respectively, and the area variation was small and without practical relevance (counties, sigma(2)=0.006; municipalities, sigma(2)=0.017). Conclusions Previous reports based on standard statistical tests are misleading. According to multilevel analysis, administrative areas have minor relevance for individual risk of T1D in Sweden. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Epidemiology and Community Health
volume
64
issue
9
pages
789 - 795
publisher
BMJ Publishing Group
external identifiers
  • wos:000281308900011
  • scopus:77957252997
ISSN
1470-2738
DOI
10.1136/jech.2008.083667
language
English
LU publication?
yes
id
329c6314-6651-46c4-bfd4-c7538b03a160 (old id 1673090)
date added to LUP
2010-09-23 12:52:06
date last changed
2018-06-17 03:32:43
@article{329c6314-6651-46c4-bfd4-c7538b03a160,
  abstract     = {Background Several European studies have found significant small area variation in the risk of childhood onset (type 1) diabetes (T1D) which has been interpreted as evidence for contextual determinants of T1D. However, this conclusion may be fallacious since the limited number of newborn infants and the low risk for T1D is a source of spurious variability not properly handled by usual statistical methods. This study investigates the existence of contextual effects in the genesis of T1D, compares conclusions in previous reports with results obtained in a multilevel regression framework and highlights analysis of variance as a useful approach in public health. Methods All singletons born in Sweden between 1987 and 1991 were identified in the Medical Birth Registry (n=560 766) and followed for diabetes until age 14 using the Hospital Discharge Registry. Area variation in the cumulative incidence of T1D was estimated by different statistical methods including multilevel logistic regression. Results The risk of T1D ranged from 4.3 to 6.5 per 1000 newborns across the counties (n=24) and from 0.0 to 19.2 per 1000 newborns across the municipalities (n=284). These differences were significant in standard statistical tests (counties, p=0.02; municipalities, p=0.007). However, according to multilevel analyses, the risk of T1D ranged from 4.7 to 5.7 and from 4.4 to 6.0 per 1000 newborns in counties and municipalities, respectively, and the area variation was small and without practical relevance (counties, sigma(2)=0.006; municipalities, sigma(2)=0.017). Conclusions Previous reports based on standard statistical tests are misleading. According to multilevel analysis, administrative areas have minor relevance for individual risk of T1D in Sweden.},
  author       = {Lynch, Kristian and Subramanian, S. V. and Ohlsson, Henrik and Chaix, Basile and Lernmark, Åke and Merlo, Juan},
  issn         = {1470-2738},
  language     = {eng},
  number       = {9},
  pages        = {789--795},
  publisher    = {BMJ Publishing Group},
  series       = {Journal of Epidemiology and Community Health},
  title        = {Context and disease when disease risk is low: the case of type 1 diabetes in Sweden},
  url          = {http://dx.doi.org/10.1136/jech.2008.083667},
  volume       = {64},
  year         = {2010},
}