Regional trend variations in infant mortality due to perinatal conditions in the Netherlands.
CONCLUSIONS
In the Netherlands, regional variations in trends in infant mortality due to perinatal conditions (1984-1994) exist, which could not be explained by health care characteristics (i.e., place or supervision of delivery and the presence of specialised neonatal care). The only sociodemographic factor that showed a consistent correlation with mortality was the percentage of Roman Catholic inhabitants of a region.


OBJECTIVE
To describe and explain regional variations in trends in infant mortality due to perinatal conditions.


METHODS
A mixed (geographical and temporal) ecological design has been used. Infant mortality due to perinatal conditions was defined as mortality in the first year of life caused by diseases of the newborn period (chapter XV of the ICD-9). Trends in sex-adjusted mortality for the period 1984-1994 as well as mortality levels at the start of this period were calculated using log linear regression. Linear regression was used to examine the association between mortality trends and starting levels on the one hand and both health care and sociodemographic factors on the other.


RESULTS
Statistically significant variations in mortality trends were found between regions. The trends in the two Southern regions were found to deviate significantly from the national trend. No strong association was found between mortality and each of the health care factors (i.e. place and/or supervision of delivery and the presence of specialised neonatal care). The only sociodemographic factor that showed consistent results was the percentage of Roman Catholic inhabitants of a region: A higher percentage in 1985 was associated with a higher mortality in 1985 and a stronger mortality decline during the period 1984-1994. This association could not be explained by parity or the age of the mother.


CONCLUSIONS
Regional differences in trends in infant mortality due to perinatal conditions in the Netherlands could not be explained by variations in health care factors. This is an important finding as the Dutch system of obstetric care, that includes a considerable number of home deliveries, has been subject to much debate. Further research that includes other causes of death and determinants is needed to unravel the causes of the trend variations.
Treurniet
H F
HF
The Erasmus University, Department of Public Health, PO Box 1738, 3000 DR, Rotterdam, The Netherlands. henriette.treurniet@rivm.nl
Looman
C W
CW
van der Maas
P J
PJ
Mackenbach
J P
JP
D000328:Adult; D002410:Catholicism; D003430:Cross-Sectional Studies; D003695:Delivery of Health Care; D005260:Female; D006801:Humans; D007223:Infant; D007226:Infant Mortality / Q000639:trends*; D007231:Infant, Newborn; D008137:Longitudinal Studies; D009426:Netherlands / Q000453:epidemiology; D010298:Parity; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology; D012959:Socioeconomic Factors