Characteristics of sanitation companies associated to water fluoridation of the supply systems of Brazilian municipalities, 2008

ABSTRACT: Introduction: The adjusted effect of the characteristics of sanitation companies on the provision of fluoridation into public water supply in Brazilian municipalities was evaluated. Methods: Cross-sectional and ecological study based on the 2010 Demographic Census, 2008 National Survey on Basic Sanitation (PNSB), and 2010 Atlas of Human Development. The independent variables were the characteristics of utilities and municipalities, and the outcome was the lack of provision of fluoridation. Prevalence ratio was estimated with Poisson regression with robust variance. Results: 5,565 Brazilian municipalities were included. In the adjusted analysis, the outcome was independently and positively associated to municipalities in the North, Northeast, Central-West and Southeast macro-regions, with coverage rates for water and sewage services below the median value, with less than 10,000 inhabitants, medium and low/very low in human development. Regarding the independent effect of the utilities’ characteristics, they were more likely not to provide fluoridation, all the companies that were not classified as indirect administration of the government or mixed-capital company or mixed-capital company of public character; municipal and intermunicipal (PR=1.21; 95%CI 1.19-1.23); and when the municipal government is the only provider (PR=1.22; 95%CI 1.20-1.25). Conclusion: The lack of provision of water fluoridation was greater when the service was mainly provided by municipal administrations and private companies associated or not to public entities, regardless of the characteristics of the municipalities.

摘要：
引言：本研究评估了巴西各市政辖区内，供水企业特征对公共供水系统实施饮水氟化（water fluoridation）的校正影响。
方法：本研究为横断面生态学研究，数据来源于2010年全国人口普查、2008年全国基本卫生调查（National Survey on Basic Sanitation，PNSB）及2010年人类发展地图集（Atlas of Human Development）。研究的独立变量为供水企业与市政辖区的特征，因变量为未实施饮水氟化服务。采用稳健方差泊松回归（Poisson regression with robust variance）估算患病率比（prevalence ratio）。
结果：本研究共纳入5565个巴西市政辖区。在校正分析中，未实施饮水氟化的情况与以下几类辖区呈独立正相关：北部、东北部、中西部及东南部宏观区域的辖区；供水与污水处理服务覆盖率低于中位数的辖区；人口不足10000的辖区；人类发展水平为中等、低/极低的辖区。针对供水企业特征的独立效应而言，未被归类为政府间接管理、公有混合资本企业或公共属性混合资本企业的供水企业，更倾向于不提供饮水氟化服务；市级及跨市级供水企业（患病率比PR=1.21；95%置信区间CI：1.19-1.23）；以及仅由市级政府作为唯一供水服务提供者的场景（PR=1.22；95%CI：1.20-1.25）。
结论：无论市政辖区的特征如何，当饮水氟化服务主要由市级行政机构及与公共实体存在关联或无关联的私营企业提供时，未实施饮水氟化的情况更为常见。