Rusiecki Jennifer A, Kulldorff Martin, Nuckols John R, Song Changhong, Ward Mary H
Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, USA.
Am J Prev Med. 2006 Feb;30(2 Suppl):S101-8. doi: 10.1016/j.amepre.2005.09.005.
Historically, prostate cancer mortality rates have been elevated in the U.S. Northern Plains states. The purpose of this study was to investigate possible contributing factors, especially whether there was any association with crop patterns.
Prostate cancer mortality rates (1950-2000) in four northern plains states (MN, MT, ND, and SD) were compared to rates for 46 other U.S. states. Within the four states, county rates in urban, less urban, and rural areas also were compared. For additional analysis, urban counties and counties with <10% of county area in crops were excluded. The average percent of county area in total cropland 1930-1950 and 1954-1974 was estimated. Using Poisson regression, we investigated whether the average percentage of county area in total cropland, 1930-1950 and 1954-1974, was associated with prostate cancer mortality rates, 1975-2000, respectively. Poisson regression analyses were also used to evaluate associations between rates and major crops, which included spring and durum wheat, winter wheat, corn, and other crops. Population centroids of the Census 2000 block groups were used to estimate the percentage of males aged 35 and older residing in close proximity to small grains crops.
Mortality rates were higher in rural compared to urban counties in 1950-2000 (rate ratio [RR]=1.032; 95% CI=1.001-1.063). Rates in 1950-1974 were significantly associated with production of corn and other crops in 1930-1950 (corn: RR per 10% increase=1.033, 95% CI=1.012-1.054; other crops: RR=1.042, 95% CI=1.021-1.063). Mortality rates in 1975-2000 were significantly associated with spring and durum wheat production in 1954-1974 (RR per 10% increase=1.042, 95% CI=1.017-1.067). Prostate cancer mortality rates increased as the percentage of population living within 500 m of small grains crops increased.
Epidemiologic studies to evaluate agricultural practices are warranted to further evaluate the observed associations.
从历史上看，美国北部平原各州的前列腺癌死亡率一直较高。本研究的目的是调查可能的促成因素，特别是是否与作物种植模式存在关联。
将美国北部平原四个州（明尼苏达州、蒙大拿州、北达科他州和南达科他州）1950 - 2000年的前列腺癌死亡率与美国其他46个州的死亡率进行比较。在这四个州内，还比较了城市、城市化程度较低地区和农村地区的县死亡率。为了进行进一步分析，排除了城市县以及作物种植面积占县面积不到10%的县。估算了1930 - 1950年和1954 - 1974年县总耕地面积的平均百分比。使用泊松回归分析，我们分别研究了1930 - 1950年和1954 - 1974年县总耕地面积的平均百分比是否与1975 - 2000年的前列腺癌死亡率相关。泊松回归分析还用于评估死亡率与主要作物之间的关联，这些主要作物包括春小麦和硬质小麦、冬小麦、玉米及其他作物。利用2000年人口普查街区组的人口重心来估算居住在小粒作物附近的35岁及以上男性的百分比。
1950 - 2000年，农村地区的死亡率高于城市县（率比[RR]=1.032；95%可信区间[CI]=1.001 - 1.063）。1950 - 1974年的死亡率与1930 - 1950年玉米和其他作物的产量显著相关（玉米：每增加10%的RR = 1.033，95% CI = 1.012 - 1.054；其他作物：RR = 1.042，95% CI = 1.021 - 1.063）。1975 - 2000年的死亡率与1954 - 1974年春小麦和硬质小麦的产量显著相关（每增加10%的RR = 1.042，95% CI = 1.017 - 1.067）。前列腺癌死亡率随着居住在距离小粒作物500米范围内人口百分比的增加而上升。
有必要开展流行病学研究以评估农业实践，从而进一步评估所观察到的关联。
