Continuing and Robust decline in sperm count in men signals catastrophic implications beyond fertility.

Courtesy: bbc.com 

A huge systematic review and meta-analysis has found a continuing decline in sperm count by an average 1.4% per year among western men between the year 1973 to 2011. The results made headlines and were published 25 July 2017 in Journal of Human Reproduction Updates. The decline of 50% in four decades was so significant that the study results made headlines.

Hagai Levine, the lead researcher and faculty member of the Braun School of Public Health and Community Medicine at Hebrew University-Hadassah in Jerusalem says, “This is a wake-up call to study the causes of this decline, aiming to prevent further deterioration.” 

Whether sperm counts have declined or not is debated since very long and the controversy remains fluid because of limited number of studies addressing this issue.

Besides being the first step in diagnosing male factor infertility, sperm count is of considerable public health importance. Reduced sperm count is a predictor of high all-cause morbidity and mortality, besides incurring a high financial burden on the society. It is also linked to a range of male reproductive problems like cryptorchidism, hypospadias, testicular cancer, low testosterone levels and increased utilization of Assisted Reproductive Techniques.  There has been a 65% increase in IVF treatments since 2003 according to a survey results of young US adults by the Reproductive Medicine Associates of New Jersey.

Low Sperm Counts is also a mirror of environmental influences on our endocrine system because of modern life style. They reflect the influence of endocrine disrupting chemicals, pesticides, changes in environmental temperature and life style factors like smoking, diet, stress and BMI.

The researchers identified 7518 studies meeting the study protocols, from which 185 studies amounting to nearly 43000 subjects who provided samples between 1973–2011 were selected for final analysis.

Data was available across 6 continents and nearly 50 countries.

For final analyses, the countries were grouped into ‘Western’ including studies from North America, Europe, Australia and New Zealand and ‘Other’/ ‘Non-Western’ including studies from all other countries like South America, Asia and Africa.

Meta- regression analyses showed that mean sperm concentration (SC) was 81 million/ml, the mean total sperm count (TSC) was 260 million and the mean year of data sample collection was 1995.

Sperm concentrations declined by 50% and total sperm count by nearly 60% over the years among men unselected by fertility primarily from North America, Europe, Australia and New Zealand. The study saw no significant declines for studies from South America, Asia and Africa, possibly because of limited number of studies available from these geographic areas. 

The statistic reflects the fact that an increasing number of men will have sperm counts below any given threshold for sub-fertility or infertility. Quite a large percentage of Western men have concentration below 40 million/ml, decreasing the probability of natural conception.

This decline remained unchanged after controlling for various confounders like age, abstinence time, method of semen collection, method of counting sperm, selection of population and study exclusion criteria, number of samples per man and completeness of data.

While it is not possible to rule out the falling trend in semen parameters in non-western countries it is certain that the decline is not as steep as observed for their western counterparts.

The continuing decline of sperm count in western males is regarded as ‘canary in the coalmine’ for male health across the life span and calls for more studies and research urgently to put a stop to this damning trend.

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