Adverse birth outcomes in the vicinity of industrial installations in Spain 2004–2008

Abstract

Industrial activity is one of the main sources of ambient pollution in developed countries. However, research analyzing its effect on birth outcomes is inconclusive. We analyzed the association between proximity of mother’s municipality of residence to industries from 24 different activity groups and risk of very (VPTB) and moderate (MPTB) preterm birth, very (VLBW) and moderate (MLBW) low birth weight, and small for gestational age (SGA) in Spain, 2004–2008. An ecological study was defined, and a “near vs. far” analysis (3.5 km threshold) was carried out using Hierarchical Bayesian models implemented via Integrated Nested Laplace Approximation. VPTB risk was higher for mothers living near pharmaceutical companies. Proximity to galvanization and hazardous waste management industries increased the risk of MPTB. Risk of VLBW was higher for mothers residing near pharmaceutical and non-hazardous or animal waste management industries. For MLBW many associations were found, being notable the proximity to mining, biocides and animal waste management plants. The strongest association for SGA was found with proximity to management animal waste plants. These results highlight the importance of further research on the relationship between proximity to industrial sites and the occurrence of adverse birth outcomes especially for the case of pharmaceutical and animal waste management activities.

Appendices

Appendix 1: Classification countries in low and medium–high income

Low-income countries

Albania, Bulgaria, Hungary, Poland, Romania, Ukraine, Latvia, Moldova, Belarus, Georgia, Estonia, Lithuania, Czech Republic, Slovak Republic, Bosnia and Herzegovina, Croatia, Slovenia, Armenia, Russia, Serbia and Montenegro, Macedonia, Burkina Faso, Algeria, Angola, Benin, Botswana, Burundi, Cape Verde, Cameroon, Comoros, Congo, Ivory Coast, Djibouti, Egypt, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Equatorial Guinea, Kenya, Lesotho, Liberia, Libya, Madagascar, Malawi, Mali, Morocco, Mauritania, Mauritius, Mozambique, Namibia, Niger, Nigeria, Central African republic, South Africa, Rwanda, Sao Tome and Principe, Senegal, Seychelles, Sierra Leone, Somalia, Sudan, Swazi, Tanzania, Chad, Togo, Tunisia, Uganda, Democratic rep. of Congo, Zambia, Zimbabwe, Mexico, Antigua and Barbuda, Bahamas, Barbados, Belize, Costa Rica, Cuba, Dominica, El Salvador, Grenada, Guatemala, Haiti, Honduras, Jamaica, Nicaragua, Panama, St. Vincent and the Grenadines, Dominican Republic, Trinidad and Tobago, St. Lucia, St. Kitts and Nevis, Argentina, Bolivia, Brazil, Colombia, Chile, Ecuador, Guyana, Paraguay, Peru, Suriname, Uruguay, Venezuela, Afghanistan, Saudi Arabia, Bahrain, Bangladesh, Myanmar, China, UAE, Philippines, India, Indonesia, Iraq, Iran, Israel, Japan, Jordan, Cambodia, Kuwait, Laos, Lebanon, Malaysia, Maldives, Mongolia, Nepal, Oman, Pakistan, Qatar, South Korea, North Korea, Syria, Sri Lanka, Thailand, Turkey, Vietnam, Taiwan, Brunei, Yemen, Azerbaijan, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan, and other countries without diplomatic relations.

Immigrants from medium–high-income countries

Austria, Belgium, Cyprus, Denmark, Finland, France, Greece, Ireland, Iceland, Italy, Liechtenstein, Luxembourg, Malta, Monaco, Netherlands, Norway, Portugal, Andorra, United Kingdom, Germany, San Marino, Holy See, Sweden, Swiss, Canada, United States of America, Australia, New Zealand, Papua New Guinea, and Tonga.

Appendix 2: Description of census variables

Data on population and housing were provided at a census section level. Average municipal values were calculated by computing, for each municipality, the weighted average of all census section’s values that comprise it.

Habitability index (0–100):

Sum of the scores of habitability in the census section/total primary residences. Each housing starts with a value of 100, and a certain amount is subtracted, to a minimum of 0, according to the following conditions:

	Scores
Initial	100
External noise, pollution and bad smells, dirty streets, poor communications, scarce green areas, crime or vandalism, lack of toilet services inside the house, no piped gas, no lift for houses in third and fourth floor, not wheelchair accessible for houses on the ground level or year of construction of the building between 1951 and 1970.	−5
Lack of hygiene inside the house, no lift for houses in floor higher than four, lack of sewerage, running water available only from private supply, only mobile heating devices available (for provinces that require it), between 5 and 10 m2 average area per capita (slightly cramped), year of construction of the building prior to 1951.	−10
Deficient status of the building.	−15
No evacuation of residual waters, no running water, dwellings above ground level not accessible to wheelchairs, not heating devices available of any kind (for provinces that require it), less than or equal to 5 m2 average area per capita (severe overcrowding).	−20
Bad status of the building.	−30
Dilapidated status of the building.	−50
Accommodation: Room that does not respond fully to the definition of family home, either because it is mobile, semi-permanent, or improvised.	−100

Unemployment rate:

Percentage of population unemployed ≥16 years old, among the total active population ≥16 in each of the census section. A person is unemployed if simultaneously:

• 1. Has no paid employment.

• 2. Looking for a job (registration in the unemployment office, workplace arrangements, responding to newspaper advertisements, etc.).

• 3. Available to work.

Economically active population is all persons ≥16 who are eligible for inclusion among the employed or unemployed groups. A person is employed if during the reference week had a payment for work.

Average socioeconomic level (0–3):

Socioeconomic status was grouped according to individuals’ occupation, activity, and employment status, and a score was assigned for each category as follows:

	Scores
<16 years	0
≥16
Unemployed seeking first job, other inactive	0
Unemployed who have previously worked, other pensioners	0.5
Residents groups, other farm workers, other personnel from service sector, unskilled workers in non-agricultural establishments, retired.	1
Agricultural employers without employees, members of agricultural cooperatives.	1.5
Rest of the administrative and commercial personnel, foremen, and boatswains of non-agricultural establishments, skilled and specialized workers from non-agricultural establishments, members of non-agricultural cooperatives, agricultural employers with employees, professionals from Armed Forces, not classified.	2
Government employees with exclusive dedication, professionals, technicians and similar that work for others, non-agricultural employers without employees, directors, and heads of farms	2.5
Directors and managers of non-agricultural establishments, senior government employees, professionals, technicians and similar that operate on their own, with or without employees non-agricultural employers with employees.	3

The resulting average socioeconomic level of the census section is an arithmetic mean of the socioeconomic level of the persons residing in the census section. 0 represents the lower socioeconomic level, and 3, the highest.

Percentage of single parent families:

Family comprised of a father or a mother with one or more children without a partner.

Number of vehicles per household:

Calculated by dividing, for each census section, the number of vehicles (cars or vans) for the number of households.

Appendix 3

Table 3 Description of industrial activity groups and total number of municipalities within a radius of 3.5 km from each type of industry

Appendix 4: Additional results for preterm birth (PTB) and low birth weight (LBW)

Fig. 4

Adjusted relative risk and 95 % CrI of PTB and LBW in municipalities within a radius of 3.5 km from each type of industry