Epidemiological study (observational study)

High incidence of acute leukemia in the proximity of some industrial facilities in El Bierzo, northwestern Spain epidem.

By: Rodriguez-Garcia JA, Ramos F

Published in: Int J Occup Med Environ Health 2012; 25 (1): 22-30

Aim of study (acc. to author)

The incidence of acute leukemia was estimated in El Bierzo, Spain. Furthermore, an analysis was conducted in order to suggest some etiological clues.

Endpoint/type of risk estimation

leukemia and lymphoma: acute leukemia (acute myeloid leukemia, acute lymphoblastic leukemia)

Type of risk estimation:

incidence

(standardized incidence rate (SIR))

Exposure

- 50/60 Hz
- magnetic field
- also other exposures without EMF
- power transmission line
- electrical substation
- residential

Assessment

calculation: distance from 39 municipalities to pollutant facilities and the point of maximal density of high-power lines

Exposure groups

Group	Description
Group 1	distance from municipality to high-power lines: < 5 km
Group 2	distance from municipality to high-power lines: ≥ 5 - < 7.5 km
Group 3	distance from municipality to high-power lines: > 7.5 - < 10 km
Group 4	distance from municipality to high-power lines < 10 km and power plant < 7.5 km

Population

Group:
- men
- women
Observation period: January 2000 - December 2005
Study location: Spain (El Bierzo)
Data source: two regional hospitals

Study size

Type	Value
Eligible	54

Statistical analysis method:

Chi-square test
Spearman's correlation coefficient, Mann-Whitney test

Results (acc. to author)

The standardized incidence rate (SIR) for acute leukemia was 5.1 cases per 100,000, surpassing the Spanish, European and world average rates (no data given in the publication). The standardized incidence rate for acute myeloid leukemia in the municipalities situated less than 5 km away from high-power lines was 5.6 cases per 100,000; in a distance less than 7.5 km 3.0 cases per 100,000, and in a distance less than 10 km 4.7 cases per 100,000. Interaction between the distance from a municipality to high-power lines less than 10 km and to a power plant less than 7.5 km was observed.
The analysis of the correlation between the annual standardized incidence rate for acute lymphoblastic leukemia and air distance to high-power lines or other industrial plants did not show any statistically significant results.

Limitations (acc. to author)

Exposure assessment is based on data at municipality level instead of individual patient data. No measurements of magnetic field strength were conducted. The results can be confounded because occupational exposure is not included in the analysis due to lack of a detailed job history.

Study funded by

Junta de Castilla y Léon, Spain

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