Abstract
Objective
The reported incidence rate of gonorrhea has more than doubled from 2000 to 2010 in Montréal, increasing in both sexes and all age groups; however, the increase was particularly high in females aged 15 to 24 years. As the reasons for this increase among young women are not fully understood, we wanted to determine whether neighbourhood-level population characteristics were associated with incidence rates in this group, to help target intervention strategies.
Methods
Incident gonorrhea cases were female residents of Montréal aged 15 to 24 years who met Québec’s gonorrhea surveillance definition, with a notification date from 2002 to 2009. Adjusted incidence rate ratios (IRR) were estimated by negative binomial regression and show the change in the incidence of gonorrhea for each unit increase in neighbourhood-level independent variables, which included material and social deprivation indices (plus the latter’s combination and components) and ethnic origin. In the final model, independent variables were normalized to facilitate comparison of their respective IRRs.
Results
A total of 837 cases were reported (cumulative incidence rate 5.6 per 100,000). Higher proportions of persons of African, Aboriginal and Caribbean ethnicity were associated with higher rates of gonorrhea, even after adjustment for deprivation indices.
Conclusion
Customary methods for gonorrhea surveillance consider individual characteristics of cases as risk factors for disease. However, our results show that gonorrhea is clustered in neighbourhoods that have high proportions of three ethnic origin groups. Findings from this ecological approach suggest that although ethnicity may be strongly correlated with socio-economic status, there are factors in ethnicity that transcend poverty.
Key words: Gonorrhea, surveillance, epidemiology
Résumé
Objectif
L’incidence signalée de la gonorrhée a plus que doublé entre 2000 et 2010 à Montréal et s’est accrue chez les deux sexes et dans tous les groupes d’âge; toutefois, l’augmentation a été particulièrement élevée chez les femmes de 15 à 24 ans. Comme les raisons de cette augmentation chez les jeunes femmes ne sont pas bien comprises, nous avons voulu déterminer si les caractéristiques de la population au niveau des quartiers sont associées au taux d’incidence dans ce groupe, pour contribuer à cibler les stratégies d’intervention.
Méthode
Les nouveaux cas de gonorrhée étudiés étaient des résidentes de Montréal âgées de 15 à 24 ans qui répondaient à la définition de la gonorrhée utilisée au Québec pour la surveillance de cette maladie, avec une date de déclaration se situant entre 2002 et 2009. Des rapports de taux d’incidence (RTI) ajustés ont été estimés par régression binomiale négative; ils montrent l’évolution de l’incidence de la gonorrhée pour chaque augmentation unitaire des variables indépendantes au niveau du quartier, lesquelles incluent des indices de défavorisation matérielle et sociale (plus la combinaison et les composants des deux indices) et l’origine ethnique. Dans le modèle final, les variables indépendantes ont été normalisées pour faciliter les comparaisons entre leurs RTI respectifs.
Résultats
En tout, 837 cas ont été déclarés (taux d’incidence cumulative de 5,6 p. 100 000). Des proportions plus élevées de personnes d’origine africaine, autochtone et antillaise ont été associées aux taux de gonorrhée supérieurs, même compte tenu des indices de défavorisation.
Conclusion
Les méthodes habituelles de surveillance de la gonorrhée considèrent les caractéristiques individuelles des cas comme des facteurs de risque de la maladie. Nos résultats montrent toutefois que la gonorrhée est regroupée dans des quartiers qui ont des proportions élevées d’habitants des trois groupes ethniques mentionnés. Les constatations de cette démarche écologique montrent que bien que l’ethnicité puisse être fortement corrélée au statut socioéconomique, il y a des facteurs dans l’ethnicité qui transcendent la pauvreté.
Mots clés: gonorrhée, surveillance, épidémiologie
Footnotes
Conflict of Interest: None to declare.
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