One in five adolescents in the world overweight: Lancet report
March 13: In 2016, a total of 324 million, or almost one in five of the world’s adolescents were overweight or obese, a 120 per cent increase from 147.3 million in 1990.
India and China together accounted for over a third (622 million – 35 per cent) of the global population of adolescents in 2016. However, while India’s adolescent population increased by 40 per cent, from 264 million in 1990 to 370 million in 2016, China’s adolescent population decreased by 28 per cent, from 352 million in 1990 to 253 million in 2016.
In the first study to track recent global changes to adolescent health in 195 countries, including India — to be published online in The Lancet on Wednesday — researchers estimate that compared with 1990, an additional 250 million adolescents in 2016 were living in countries where they faced a triple burden of infectious disease, non-communicable diseases including obesity, and injuries, including those sustained from violence.
In 2016, a total of 324 million, or almost one in five of the world’s adolescents were overweight or obese, a 120 per cent increase from 147.3 million in 1990. While an even higher proportion of US adolescents were found to be obese or overweight (44 per cent of young women and 45 per cent of young men), according to the report, both India and China saw a significant increase in the prevalence of overweight and obese adolescents. Young Chinese women experienced an annual increase of nearly 5 per cent while young Indian women experienced an annual increase of almost 9 per cent.
On the other hand, anaemia affected almost one in four adolescents globally (430 million, 24 per cent) in 2016, an increase of 20 per cent from 357 million in 1990. The prevalence of anaemia in young women in countries like India and Bhutan was over 50 per cent.
In 2016, worldwide, 136 million adolescents smoked daily (112 million males and 25 million females), a decrease of 38 million compared with 1990. In China in 2016, 20 per cent (26.8 million of 134.4 million) of young males were smoking daily compared with 1 per cent (1·4 million of 118·3 million) of young females.
The study found that prevalence of smoking was increasing in India (6.4 per cent annual increase for female adolescents and 0.4 per cent annual increase for male adolescents), although the prevalence in 2016 was relatively low, with 3 per cent (4.3 million of 175.1 million) of female adolescents and 8 per cent (14.8 million of 195·0 million) of male adolescents smoking daily.
The prevalence of binge drinking in 2016 among female adolescents in India was low at 1 per cent (0.5 million of 58.7 million) as against 8 per cent for female adolescents (2.7 million of 35.8 million) in China. For male adolescents, it was 3 per cent (2.0 million of 65.4 million) in India, as against 15 per cent (9.4 million of 63.6 million) in China.
Globally, the number of 15-24 year olds who are not in education, employment or any kind of training is estimated to be around three times higher for younger women adolescents (175 million) than young men (63 million). In India, the prevalence is over 15 times higher in young women than in young men (nearly 54 per cent compared to 3.5 per cent).
Professor George Patton from the Murdoch Children’s Research Institute and University of Melbourne, who in 2016 led The Lancet Commission on adolescent health and well-being, said despite improvements in various settings, the adolescent health challenge is greater today than it was 25 years ago.
Study reveals reason behind loss of hearing after exposure to loud sounds
March 10: A recent study has discovered the reason behind the hearing loss after we listen to loud noises or sound. The study published in the journal ‘Proceedings of the National Academy of Sciences’ explains the science behind our ears feeling numb and losing the sense of hearing temporarily.
“Most people have experienced that their hearing is impaired and the ear feels numb after listening to loud sounds. After a while hearing returns to normal. We have discovered that a tiny structure in the cochlea known as the tectorial membrane plays an important role in this process, by acting as a storage depot for calcium ions. These calcium ions contribute to regulating the function of the sensory cells”, said lead study author Anders Fridberger.
Calcium ions, which are calcium atoms with a positive charge, play a key role in the processes that make hearing possible. The conversion of sound waves to nerve impulses takes place in the inner ear, also known as the cochlea, which looks like the spiral shell that some snails have. The cochlea contains many sensory cells, which detect sounds and generate signals that are passed on to the brain.
Previous research has shown that the fluid that surrounds the sensory cells in the cochlea has a low concentration of calcium ions. There were, however, questions surrounding this, because sensory cells that are placed in fluids with the natural level of calcium no longer work normally.
When the scientists added a substance that mops up calcium ions, the sensory cells ceased to function. In the next step, they exposed the inner ear to noise levels that correspond to those experienced at rock concerts, which had the same effect.
The research group is now planning to investigate whether the same mechanism is important in age-related hearing impairment.
Vitamin D may help control asthma
March 10: Besides making bones strong, higher levels of Vitamin D can also help children with asthma to become more resilient to harmful respiratory effects caused by indoor air pollution, say researchers including one of an Indian-origin.
“Asthma is an immune-mediated disease,” said lead author Sonali Bose, Assistant Professor at the Icahn School of Medicine at Mount Sinai. “From previous scientific studies we knew that vitamin D was a molecule that may influence asthma by impacting antioxidant or immune-related pathways,” she added.
The researchers observed that having low blood vitamin D levels was related to harmful respiratory effects of indoor air pollution from sources such as cigarette smoke, cooking, burning of candles, and incense, among children with asthma.
Conversely, in homes that had the highest indoor air pollution, higher blood vitamin D levels were associated with fewer asthma symptoms in children. Importantly, the findings showed that the effects were most pronounced among obese children, Bose said.
“This highlights a third factor at play here - the obesity epidemic - and helps bring that risk to light when considering individual susceptibility to asthma.”
For the study, published in the Journal of Allergy and Clinical Immunology: In Practice, the researchers tested three factors - air pollution levels in homes, blood vitamin D levels, and asthma symptoms - in 120 schoolchildren with pre-existing asthma. One-third of the children were obese.
“One way to increase blood vitamin D levels is to increase sun exposure, but that isn’t always possible in urban environments, or in people with darker skin pigmentation,” Bose said.
“Another way is through dietary supplements or eating more foods that are high in vitamin D, such as fatty fish, mushrooms, or foods fortified with vitamin D, such as bread, orange juice, or milk.”