| ObjectiveThis present study was to explore the cancer risk of long-term community-level pentachlorophenol(PCP) exposure in a general population, through investigating the cancer spectrum and PCP exposure level of Schistosomiasis endemic areas.MethodsIncident cancer cases from 2011 to 2014 were identified and complemented by interviewing with each community healthy service centre. The historical data of PCP usage was collected through interviewing Guichi Station of Schistosomiasis Prevention and Control in Chizhou City, and PCP concentration of raw drinking water samples in each district was measured by gas chromatography-tandem mass spectrometry(GC-MS-MS) analysis, and we integrated these information to evaluate the pentachlorophenol exposure levels, then divided the study area into three PCP exposure categories(high, medium and low exposure groups) by the inter-quartile range. The crude cancer incidence and age-standardized rate were calculated by using the annual incident cancer cases, stratified by gender, age, tumor type, and PCP exposure categories, respectively. The cancer risk of long-term PCP exposure was evaluated by standardized incidence ratios(SRRs) with 95% confidence intervals(95%CIs), using low exposure group as the reference.ResultsA total of 3503 cancer incident cases(2130 male and 1373 female cases) were identified, the crude cancer incidence was 286.06 per 100 000 person-years(352.77 per 100,000 person-years for males and 221.17 per 100,000 person-years for females), and the age-standardized rate was 197.12 per 100,000 person-years(225.83 per 100,000 person-years for males and 164.67 per 100 000 person-years for females). The incidence of all cancers in males was higher than that in females(male/female SRR=1.37), and the incidences of respiratory, digestive and urinary system cancers in males were 2 times greater than that in females, but the incidences of endocrine and reproductive system cancers in females were 4 ~ 5 times higher than that in males. The median age of cancer cases was 62 years old, and males were older than females(64 vs. 58 years old). Digestive system cancer was the top one in all system cancers, with a 112.29 per 100,000 person-years of age-standardized rate, and accounted for 58.5% of the total.From 2011 to 2014, the age-standardized rates of high, medium and low exposure groups were 244.14 per 100,000 person-years, 182.33 per 100,000 person-years and 155.90 per 100,000 person-years, respectively. And the incidence of high exposure group was the highest(high/low SRR = 1.57). The SRRs of most cancers were probably increased with age. As the rise of PCP exposure level, the incidences of digestive, endocrine and reproductive system cancers were increased significantly, and the incidences of thyroid cancer(high/low SRR = 6.67, moderate/low SRR = 4.51), prostate cancer(high/low SRR = 2.30, moderate/low SRR = 1.76), stomach cancer(high/low SRR = 2.06, moderate/low SRR = 1.51), liver cancer(high/low SRR = 1.71, moderate/low SRR = 1.17) in males and liver cancer(high/low SRR = 1.74, moderate/low SRR = 1.14), thyroid cancer(high/low SRR = 2.18, moderate/low SRR = 1.46), uterine cancer(high/low SRR = 1.64, moderate/low SRR = 1.16) in females were increased particularly. In addition, the incidences of lymphoma, kidney cancer and bladder cancer of males and lymphoma and mesothelial and soft tissue of females probably increased with the elevated PCP exposure level.ConclusionsIn the research area, respiratory, digestive and urinary system cancers were typically occured in males, while endocrine and reproductive system cancers were occured principally in females. And the difference of susceptibility of cancer between genders was clearly observed. Digestive system cancer occupied the most of the cancers occurring in this study area, and the incidence of gastric cancer was the highest in both males and females. Middle-aged and old people were the high risk population of malignant neoplasm, therefore the healthcare of them should be strengthened and improved.Long-term community-level PCP exposure was probably associated with increasing incidence of digestive, endocrine, and reproductive system cancers, which might increase along with age, and the association between PCP exprouse and reproductive system cancer increased obviously. Long-term community-level PCP exposure might strong associate with increasing incidence of thyroid, prostate, gastric and liver cancers of males and liver, thyroid and ovarian cancers of females. |
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