Historical evidence that residential electrification caused the emergence of the childhood leukemia peak.

A peak in childhood leukemia, ages two through four, emerged de novo in the 1920s in the United Kingdom and slightly later in the United States (US). Electrification in US farm and rural areas lagged behind urban areas until 1956. In recent years, childhood leukemia has been associated with residential electromagnetic fields. During 1928-1932, in states with above 75% of residences served by electricity, leukemia mortality increased with age for single years 0-4, while states with electrification levels below 75% showed a decreasing trend with age (P = 0.009). During 1949-1951, all states showed a peak in leukemia mortality at ages 2-4. At ages 0-1, leukemia mortality was not related to electrification levels. At ages 2-4, there was a 24% (95% confidence interval (CI), 8%-41%) increase in leukemia mortality for a 10% increase in percent of homes served by electricity. The childhood leukemia peak of common acute lymphoblastic leukemia may be attributable to electrification.