mercredi 30 novembre 2016

Sick men of Asia

Study: China's sperm is getting worse
By Yuan Yang and Hudson Lockett

Beijing’s efforts to reinvigorate China’s birth rate, one of the lowest in the world, face a serious obstacle as semen quality plummets among young male donors, research suggests.
Last year fewer than a fifth of young men who donated sperm in the inland province of Hunan had sufficiently healthy semen to qualify as a donor, according to a 15-year study of more than 30,000 applicants. 
In 2001 more than half qualified.
Local media reports indicate Hunan is not the only province suffering a shortage in qualified donors. State broadcaster China Radio International recently reported that a sperm bank in Henan province had dropped minimum height and education requirements for donors and was offering to store their semen free of charge for three decades in an effort to make up its own deficit.
“Growing evidence seems to suggest that male infertility is increasingly becoming a serious concern in the entire country,” said Huang Yanzhong, senior fellow for global health at the Council on Foreign Relations in New York. 
If shown to reflect a broader trend, such findings would further complicate China’s mounting demographic problems.
China’s fertility rate — the number of children a woman is expected to have during her child-bearing years — was 1.05 last year, according to data from the Chinese government’s annual “1 per cent” population survey, which polls about 17m citizens each year.
The bottom territories in a World Bank 2014 survey — South Korea, Portugal, Hong Kong and Macau — had fertility rates of 1.2, against a global average of 2.5. 
That survey estimated China’s fertility at 1.6, still far below the 2.1 births per woman needed to keep a country’s population from shrinking.
China is ageing rapidly, leading to a shortage of young workers and warnings of a pensions crisis, but its fertility rate has long been in decline. 
From a peak of 6.4 births per woman in 1965 it had fallen to 2.8 by 1979, the year the notorious one-child policy was introduced amid fears of runaway population growth. 
That regime led to widespread sex-selective abortion, resulting in a significantly skewed sex ratio.
The blanket policy was scrapped late last year for a two-child policy. 
But previous loosening of the old policy has fallen short of policymakers’ hopes in raising the country’s birth rate, with many Chinese couples apparently unwilling to take advantage of the chance to have a second child.
“The situation is probably worse than expected,” said Mr Huang, noting that the results of a government-commissioned national study on infertility in China that had been scheduled to end in 2011 had still not been made public. 
Some researchers also say previous census results have been manipulated by family planning officials in regions with a pro-birth policy, who inflate birth rates in order to make their policies look more effective.
The researchers in the Hunan semen study, published online in the journal Fertility and Sterility, say there is no clear explanation for why donors’ reproductive health declined so rapidly. 
But they point to “increased environmental pollution, including pollution of water, air and food”, as a possible explanation.
However, World Health Organisation spokesperson Tarik Jašarević said the WHO could not yet determine with certainty which factors had caused deterioration in certain or multiple countries, as studies often employed different methodologies to analyse semen
He also cautioned that semen quality did not necessarily correlate directly with male fertility.
“It should be noted that male reproductive health can be affected by many complex factors,” including lifestyle, the environment and concomitant diseases, he said. 
“More research is needed to enable sound guidance or policy advice concerning deteriorating semen quality.”

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