State Study Finds No Link of Cancer to Farm Areas
A state investigation into whether children in California’s agricultural heartland are more likely than others to develop childhood cancers has found no evidence that the mysteriously high cancer rates in towns like McFarland, Earlimart and Rosamond afflict the entire region.
The Department of Health Services study released here Friday found that the overall cancer rate among children under 15 in the southern San Joaquin Valley was no different from that reported in Los Angeles County, the San Francisco Bay Area and in other regions of the United States.
The two-year study also found that children in the valley’s urban areas had higher cancer rates than those in its rural, agricultural areas--a finding that seems to challenge the widespread suspicion that the McFarland cancer cluster is related to agricultural chemicals.
“Throughout the region as a whole, we don’t see rates like McFarland,” said Dr. Lynn R. Goldman of the state health department. The childhood cancer rate in the tiny farming town has been found to be three times as high as for a town its size.
The new findings may offer some reassurance to residents of the region, some of whom have feared an epidemic of pesticide-induced cancers. In recent years, McFarland had become a symbol of public fears about pesticide use, and an assortment of celebrities, politicians and others flocked there to express those fears.
But the absence of a region-wide pattern of high cancer rates underscores the difficulty of ever identifying the causes of specific clusters.
“This type of an assessment can only go so far,” said Dr. Kenneth W. Kizer, director of the health department, at a public hearing Friday in McFarland. “It’s just the nature of the tools. They may not be able to tell us the answer to the question that the community wants to know.”
Unusually high rates of childhood cancer have turned up over the past few years in McFarland, Rosamond and Earlimart. McFarland and Earlimart are farm towns in Kern County and Tulare County, respectively; Rosamond is a desert community in southern Kern County long popular with smelters and junkmen dumping industrial waste.
Two years ago, after investigations of water, soil and household chemicals in McFarland failed to turn up any obvious local cause of the cancers, the state health department decided to study a broader, four-county region to see whether the problem might be endemic to the region.
The department found 402 cases of childhood cancers diagnosed between 1980 and 1988 in Fresno, Kern, Kings and Tulare counties. About one-third of those were leukemia cases. Nearly one-fifth were brain cancers. The others included kidney, soft-tissue, bone and eye cancers.
The overall rate was 12 to 13 new cases per 100,000 children each year, according to the draft report released Friday, which is typical of rates in other regions of the country. According to Kern County figures, McFarland has a childhood cancer rate of 36.7 cases per 100,000, while in Rosamond the rate is 72 per 100,000. In Earlimart, the state has said there is an “excess” of childhood cancers.
The state found no significant differences between the rates among Anglos and Latinos, and no significant differences among the four counties.
They did, however, find slightly higher cancer rates among children in the cities of Fresno and Bakersfield. They found slightly lower rates in rural areas not used for farming. State officials said the rates in rural agricultural areas were about average.
Goldman, the pediatrician and toxicologist who headed the study, said the higher urban rates are typical of the country at large. The reason for the urban-rural difference is not known; some researchers suspect environmental influences, while others wonder whether urban cases are simply more often reported.
State health officials warned, however, that there are limitations to their study: They had no information on the children’s exposure to possible carcinogens, nor did they know the parents’ occupations, whether children had lived elsewhere before diagnosis and whether other children became ill after moving away.