Study On The Influence Of Coal-burning Fluorine Exposure To Male Infertility And Urinary Fluoride

Objective: To explore the differences of the content of urinary fluoride between the different coal-burning fluoride exposure areas, and discuss the impact of coal-burning fluoride exposure on the male infertility; so as to provide important scientific basis and strategies or measures to prevent and control the harm of fluorosis on male infertility.Methods: 1. General risk factors(eg. alcohol) on the male infertility were reviewed and assessed by conducting a meta-analysis in order to provide direct basis for designing questionnaire on the subsequent research.2. Case-control study: in our study, subjects were divided into the reproductive dysfunction group(case group, n1=145) and normal reproductive function group(control group, n2=82), then fluorine exposure related factors including their living environment, diet, fertility, etc. were collected, then non-conditional Logistic regression analysis were conducted after the database was established by Epidata3.0 software.3. Field surveys: according to the information from 2011 Endemic Disease Control Office of Guizhou, Guizhou Province was divided into high- and low-fluoride regions, then a multistage stratified random sampling method was used, some district or county were randomly selected from high- and low-fluoride regions respectively, and then townships, finally to individuals. The fluorine exposure related factors including their living environment, diet, fertility condition were collected from the severe fluorosis region—Bijie, as the high-fluorine-region group(n1=67) and the surrounding region from Bijie as low-fluorine-region group(n2=38) in our survey, then the database was established by Epidata3.0 software. Simultaneously crops, foods were collected, and their fluoride contents were measured according to "the Determination of Fluorine- ion Selective Electrode Method"(GB/T5009.18- 2003). After that, the objects’ random urines were measured using the "Determination of Urinary Fluoride- Ion Selective Electrode Method"(WS/T89-1996).4. All statistical analyses were conducted by Review Manager 5.0.25 and SPSS 18.0 softwares.Results: 1. Six controlled studies on alcohol drinking and male infertilit y we r e i n cl u d e d. Th re e i n d i ce s i n cl u d i n g t h e sperm density(SD), sperm energy a+b(SE a+b), and the rate of teratospermia(RT) were focused. The combined mean difference(MD) were-1.81, 95%CI(-4.68~1.06) in SD,-8.39, 95%CI(-19.22~2.43) in SE a+b, the differences of SD and SE a+b between the drinking and non-drinking groups were not statistically significant(P>0.05); while the MD was 7.20, 95%CI(1.62~12.78) in RT, the difference of rates of teratospermia between the drinking and non-drinking groups was statistically significant in our meta-analysis.2. Case-control study: Infertility risk factors included age(OR=3.52), smoking(OR=1.75), ingle drying of staple food(OR= 4.25) and less washing before cooking(OR=2.19), while education(OR=0.37) was the protective factor. Moreover, low fertility risk factors included age(OR=5.64), drying the staple food using ingle(OR=4.24), less elutriation before cooking(OR=3.77), and like drinking self-made tea(OR=3.62) at home, while staple food airtight storage(OR=0.58) was the protective factor.3. Field surveys: Significantly different on the urinary fluoride were found between groups those were with or without children( ?2=20.62, P<0.001), and their wife have or not miscarriage( ?2=5.67, P=0.017). Hazards factors of the fluoride content in urinary of coal-burning fluoride exposure area included the home-used ingle had not been improved, dental fluorosis, food storage opened, like drinking tea, ingle drying of staple food, less elutriation before cooking(only one or less), and dental fluorosis.Conclusion: 1. Alcohol drinking is a risk factor to male infertility; and its main harm was to increase the rate of teratospermia.2. Coal-burning-type fluorine exposure can increase the risk of male infertility, and the factors including ingle drying of staple food and less elutriation before cooking were the risk factors of male infertility in coal-burning-type endemic fluorosis areas.3. We can reduce the occurrence of fluorosis by reducing the accumulation of fluoride, for example, change the living environment(eg. the home-used ingle had been improved) and diet(eg. food enclose storage, less drinking self-drying tea, less or not use ingle drying of staple food and more elutriation before cooking) in coal-burning fluoride exposure area. If that, it should reduce the risk of infertility and/or miscarriages.4. Reducing the possibility of male infertility risk in coal-burning fluoride exposure area should take some efforts and measures such as changing the life habit by oneself(e.g. the home-used ingle had been improved, food enclose storage, less drinking self-drying tea, less or not use ingle drying of staple food, more elutriation before cooking.