Exposure to a chemical in tobacco smoke could make it more difficult for people to see in low-contrast conditions, such as low light, fog or glare, a new study suggests.
Researchers found that higher levels of cadmium in the blood were associated with diminished contrast sensitivity, they report in JAMA Ophthalmology.
“This particular aspect of vision is really important because it affects your ability to see the end of a curb or put a key into a lock in low light,” said lead author Adam Paulson of the University of Wisconsin, Madison, School of Medicine. “It’s something that at this point in time there’s no way to correct, unlike visual acuity, which you can easily correct with glasses or contact lenses.”
Smoking can raise cadmium levels, as can consumption of leafy green vegetables and shellfish, Paulson said. It may be possible to eat greens and avoid cadmium if you can find produce that has not been treated with pesticides, he added.
For a closer look at the impact of two heavy metals, cadmium and lead, Paulson and his colleagues analyzed data from a larger study dubbed the Beaver Dam Offspring Study, which was designed to look at the aging process. Volunteers enrolled in that study between 2005 and 2008.
Both lead and cadmium accumulate in the retina, Paulsen said.
The retina is the layer of nerve cells at the back of the eye that senses light and sends signals to the brain.
Volunteers’ contrast sensitivity was examined through an eye test. Instead of making letters smaller and smaller, researchers made successive reductions in the contrast between the letters and the background. Volunteers would start with black letters against a white background. Then, with each iteration, the letters would become more and more washed out.
At the beginning of the study, all 1,983 participants had no impairment. All were retested at five and 10 years after the study started. At the 10-year mark, nearly one quarter of the study volunteers had some impairment of their contrast sensitivity, and that impairment was associated with levels of cadmium, but not lead.
That doesn’t necessarily mean that lead won’t impact contrast sensitivity. “Levels of lead in our study population were actually quite low,” Paulsen said. “It could be that in our study there wasn’t enough exposure to lead. It’s possible that another study might find an association.”
The new study suggests “that certain trace chemicals that we are exposed to in small amounts could be harming our eyes in subtle, incremental ways over time,” said Dr. Mandeep S. Singh of the Wilmer Eye Institute at Johns Hopkins Medicine. “Here, the investigators implicate cadmium, which is present at relatively high levels in cigarette smoke, but there could be other culprits which we don’t know about. But it is another good reason to avoid smoking.”
Many people don’t realize they can have good visual acuity, 20-20, and still not feel like they can see well, Singh said in an email. “Even people who can read all the way down to the smallest letters on the eye chart can have deficits in contrast sensitivity that tells us their vision is not OK.”
Cadmium is a neurotoxin, and it could be damaging the nerve cells of the vision system, Singh said.
Even those with 20-20 vision can experience problems with daily living if their contrast sensitivity is impaired, said Dr. Nicholas J. Volpe, George and Edwina Tarry Professor and chairman of the department of ophthalmology at Northwestern University’s Feinberg School of Medicine in Chicago.
Contrast sensitivity declines as we age, Volpe said. But the new study suggests there might be other factors that can affect it.
Volpe cautioned that the study has found an association, but it can’t prove that cadmium actually causes contrast sensitivity to decline. It’s possible cadmium is a marker for some other factor.
Another issue is that the researchers weren’t able to say that cadmium, independent of smoking, was associated with contrast sensitivity declines, Volpe said. So, until there are more studies, “I don’t know that we’ll be checking cadmium levels,” he said. “More often I’ll be saying, don’t smoke.”
This winter control asthma with inhalation therapy
Whether youre indoors or outdoors, winter will exacerbate asthma attacks. Winter is the most loved season, but it might be unpleasant for patients with lung diseases. An American Lung Association fact-sheet states that asthma is one of the most common chronic disorders and currently affects about 7.1 million children under 18 years. The World Health Organisation Global Burden of Disease Study estimates that 13.8 million disability-adjusted life years (DALYs) are lost yearly due to asthma, representing 1.8 per cent of the total global disease burden.
For 300 million people around the globe suffering from asthma, the cold winter months often lead to a worsening of their symptoms.
The cold environment it not suitable for asthma patients. Their lungs and airway passages are quite sensitive. To a larger extent, asthma symptoms related to winter can be in controlled and managed by precise treatment and medication. Due to the swelling in the lining of the airways which leads to their narrowing, and the sticky mucus or phlegm build-up that blocks the airways, breathing is difficult and forced for asthmatic patients.
During winter, the cold air causes airways to tighten further, making it even more difficult to breathe.
Many patients and their family members are misinformed about the causes of asthma and the treatment options available. It is a necessity to educate patients and caregivers about the disease and treatment with minimal side-effects of inhaled corticosteroids, i.e. inhalation therapy.
Many pharmaceutical organisations are running campaigns to bust myths around inhalation therapy. Often, the word steroids evokes apprehensions in the minds of patients causing them to shy away from inhalers. The steroid is produced by the human body naturally to deal with inflammation and it is also safe for children and pregnant women. The inhalation therapy consists of an inhaler pump to send the corticosteroids into airway passages.
According to a research article published in Respiratory Medicine journal, the correlation between inhalation therapy for asthma and clinical efficacy is positive, with improved symptom-control and lung-function shown in most studies of adults, adolescents and children.
In the inhalation therapy, the inflammation of the airway requires a very small quantity of corticosteroids — around 25 to 100 micrograms — but when it is consumed through the oral/intestinal route the amount administered is very large — about 10,000 micrograms, since only a fraction of the drug reaches the lungs. This means that every time an asthma patient pops a pill or a tablet, he/she is actually taking almost 200 times the amount of medication required, leading to ill-effects on health.
Inhalation therapy directly gives body only that amount of steroid needed to control the symptoms. Against this, oral medication first gets dissolved in the blood and then reaches various organs, including the lungs.
Thus, inhalation therapy is a simple and easy solution for asthma patients to enjoy their winter to the fullest.
Some nose, throat bacteria less likely to develop into flu: Study
US researchers have identified a cluster of nose and throat bacteria that made their hosts less likely to get flu.
The researchers from the University of Michigan (UM) looked at samples of nose and throat bacteria and used DNA sequencing to identify which bacteria were present.
Analysing the bacterial composition across all samples, they found five clusters.After taking into account other known factors that could affect an individual’s
susceptibility to influenza, such as age, exposure to tobacco, crowded household and flu vaccination, the researchers then looked to see if individuals with a given cluster were less likely to get influenza.
“We looked at who had which cluster and whether it makes a difference on whether they got influenza, and it does,” said lead author Betsy Foxman, Professor at UM. “That’s the exciting thing about it. It tells us if you have this bacterial community, you have lower risk for getting the flu. That’s big news because it really hasn’t been shown before.”
However, the findings published in PLOS ONE journal also bring new questions.”Is it really possible to push someone’s microbiome in a way that would make a difference? Is it possible that we could tell people – ‘Here’s your microbiome pill?'” Foxman said, adding that “It’s a very long road and we’re at the beginning.”
Researchers hope that similar studies can be done in a different population and possibly follow them longer for secondary bacterial infections.”We know we are always going to need new antibiotics but this way we could hold on to them longer and, presumably, if we could intervene in this way there would be fewer side effects,” Foxman said.
For the study, the team enrolled 717 participants from 144 households. Household members of individuals with confirmed influenza were recruited for the study and followed for 13 days or until they developed influenza, whichever came first. They included only the 537 individuals who tested negative for influenza at the beginning of the study.
Taking artificial sweeteners as a sugar substitute? Study says it may not be effective
While some people who are trying to avoid sugar are increasingly opting for artificial sugar, a recent study has revealed that taking artificial sugar may not be a good idea after all.”Growing concerns about health and quality of life have encouraged people to adapt healthy lifestyles and avoid the consumption of food rich in sugars, salt, or fat to prevent obesity and other non-communicable diseases. With increased consumer interest in reducing energy intake, food products containing non-sugar sweeteners (NSSs) rather than simple sugars (monosaccharides and disaccharides) have become increasingly popular”, the study stated.
But replacing sugar with artificial sweeteners used in Diet Coke and other soft drinks has no effect on weight loss and their long-term health effects are still poorly understood, the review said. The study titled ‘Association between intake of non-sugar sweeteners and health outcomes: systematic review and meta-analyses of randomised and non-randomised controlled trials and observational studies’ was led by the University of Freiburg and published in the BMJ.
It also highlighted the absence of research on the long-term health effects of sweeteners when taken over years or decades. In this comprehensive systematic review, a broad range of health outcomes was investigated to determine a possible association with non-sugar sweetener used by a generally healthy population.
“The studies were set up to look at different types of sweeteners, measuring weight, blood sugar (glycaemic) control, oral health, cancer, cardiovascular disease, kidney disease, mood and behaviour in consumers. For most of them, there was no statistical difference in weight loss or health benefits of adults and children using higher doses of sweeteners rather than small amounts or none”, a report in The Guardian stated.
This comprehensive systematic review covers a broad range of benefits and harms of NSSs in a generally healthy population of adults and children, following rigorous systematic review methods. “Overall, we included 56 studies of adults and children, which assessed the associations and effects of NSSs on different health outcomes.
For most outcomes, there seemed to be no statistically or a clinically relevant difference between NSS intake versus no intake, or between different doses of NSSs. No evidence was seen for health benefits from NSSs and potential harms could not be excluded. The certainty of the included evidence ranged from very low to moderate, and our confidence in the reported effect estimates is accordingly limited”, the study stated.