Environment, Nutrition, Toxicology and Reproduction
(W234) GEOGRAPHIC VARIATION IN SEMEN QUALITY: META-ANALYSIS OF SEMEN QUALITY LITERATURE.
Phillips, Karen1, Walker, Mark1, 2, Weselak, Mandy2, 1 University of Ottawa, Ottawa, ON, Canada2 Ottawa Health Research Institute, Ottawa, ON, Canada
ABSTRACT- Global changes in sperm concentration coincident with increased used of anthropogenic products (e.g. pesticides, plastics, electronics) have been argued to be preliminary evidence for a causal association with environmental chemicals called endocrine disrupters. Current classification standards used to assess semen quality do not reflect the degree of variation that may be representative of normal parameters for healthy men of different ages, ethnicities or geographical residence. Geographic variation in semen quality may reflect differences in semen collection methodologies, racial or ethnic variation, or may be representative of differential exposures to environmental agents. While meta-analyses have been done to investigate temporal changes in semen quality, large meta-analyses examining narrow geographical trends in semen quality parameters have not been published. Previous meta-analyses have been criticized for failing to consider selection bias, age, abstinence time and regional variation. Over the past 7 years, a number of semen quality studies have been published, enabling geographic variation to be analyzed using narrower subgroups. Using Medline, Embase and hand searching of journals, a literature search will be conducted using keywords: human, semen quality, semen parameters. Literature will be evaluated using the following criteria: participants (sample size, health status, age), semen quality data (semen analysis methods, semen parameters (motility, morphology, concentration, volume), abstinence period) and study design. Data will be abstracted by two reviewers. A preliminary scan of the literature has identified studies reporting semen quality parameters in men representing 25 different nations, published between 1997 and 2004. Principally these studies use a cross-sectional design with variation in type of participant population (sperm banks, fertility clinics and occupational cohorts), semen analysis methodology, year of collection and sample size. These variables will be considered in our expanded evaluation of semen quality literature published 1997-2004. Evaluation of geographic variation is essential to our understanding of male reproductive health, environmental exposures and to accurately describe temporal changes in global semen quality.
KEY WORDS: environment, fertility, semen, sperm