The "Fifty Shades of Grey effect" has been blamed for the rise of sexually transmitted infections and diseases among older couples. A top doctor said the popular Fifty Shades of Grey trilogy has led older couples to be more "adventurous in bed", according to The Independent.

Dr Charlotte Jones said the bestselling trilogy could explain the increase in STIs or STDs among couples between 45 and 50 years of age. The popularity of the erotic series has led to its movie version due for release on Valentine's Day 2015 starring Jamie Dorman as billionaire Christian Grey.

Dr Jones, British Medical Association GP committee chairperson, said the worldwide success of the E.L. James novels has given couples more confidence in sex but failing to use proper protection. She said the Fifty Shades of Grey effect makes older couples more "explorative" without thinking about using a condom necessarily.

In a report by The Independent, she revealed other doctors have observed rising cases of syphilis and gonorrhea along with the more common infections like chlamydia and thrush. Jones advised people to see a doctor if they notice any symptoms of STDs. She said patients should not be embarrassed since doctors will not be surprised to see such cases.

The erotic novel trilogy by E.L. James has themes of "bondage" and "sado-masochism" according to the Independent. The books have since sold over 100 million copies since the book has been published in 2011.

According to figures from the Public Health England, there were 1,281 new cases of STIs among people aged 65 and up. The number rose by over 7 per cent at 1,374 in 2012. In 2011, there were 19,896 cases of infections among people aged 45 to 64. The figure increased by almost 3 per cent at 20,445 in 2012.

STD among the elderly

In the U.S., chlamydia infections among Americans over 65 years old rose by 31 percent while syphilis cases increased by 52 percent based on a report by the Centers for Disease Control. According to the National Survey of Sexual Health and Behavior, only 6 percent of seniors aged 61 and up use condoms in sexual encounters.

Doctors have advised older couples to use condoms and protect themselves from sexually transmitted diseases.