Sunshine actually may put pep in your step and improve your thinking skills. A study by the University of Alabama at Birmingham shows that the amount of sunlight you are exposed to may boost your cognitive ability.

The study examined the seasonal role and amount of sunlight exposure (referred to as insolation) on patients’ energy levels and cognitive ability. Researchers hypothesized that greater insolation would boost both energy and mental functioning.

This was found to be very true for patients with depression. Sunlight plays a huge role in the body’s circadian (daily) rhythm. Alzheimer’s, for example, has been associated with low blood flow to the cerebrum, yet another of sunlight’s effects.

Individuals who got less sun exposure were more likely to experience an irregular circadian rhythm, similar to Seasonal Affective Disorder (SAD), also known as seasonal depression. Several studies have been conducted in the past to examine the effect of sunlight and seasonal changes on mood in people with depression, but this was the first to study the effects of both on thought processes.

"We think some of the same physiological mechanisms that affect depression also affect cognitive function,” says Shia Kent, author of the study and doctoral candidate at the School of Public Health at the University of Alabama at Birmingham. “These same hormone systems have been implicated in a number of mental disorders and cognitive disorders.”

One key to this relationship lies in the suprachiasmatic nuclei (SCN), a region of the brain responsible for processing information from the eyes and stimulating hormones.One of the SCN’s roles is to prevent the pineal gland from converting serotonin into melatonin, a hormone that triggers sleepiness.

The retina sends light information to the SCN, slowing the brain’s production of melatonin and serotonin—both associated with cognitive functioning—during the day or in a well-lit room. Without this process, the body’s natural rhythm is disrupted. Similar disruptions have been associated with sleep disorders and memory problems in otherwise healthy individuals.

Participants in the study hailed from an area of the United States known as the “stroke belt”—Arkansas, Louisiana, Tennessee, Mississippi, Alabama, Georgia, North Carolina, and South Carolina. Nearly 14,500 men and women over age 45 (44% African-American, 56% white) with no history of a stroke included in the final model were questioned using the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study.

Cognitive functioning was measured via telephone interviews, while weight, height and blood pressure were measured in-home prior to the study. Participants were then followed for the next two weeks, while researchers measured insolation (with the help of NASA satellite and ground data) and thinking ability (using questionnaires).

Solar radiation was measured eight times daily, at 3-hour intervals. Typical insolation values were 25,000-30,000 KJ/m² in late spring and early summer, and 8,000-10,000 KJ/ m² in the central U.S. Short-term and long-term memory were measured using a six-question test. Answering four or less correctly indicated impairment. 

Based on their findings, researchers reported that low sunlight exposure was a higher likelihood of cognitive impairment for subjects with depression, including those who were prone to SAD. Roughly 18% of participants with any form of depression were classified as having impaired thinking in response to lower insolation, regardless of the season.

“This is speculation,” says Kent, “but those who have cognitive impairment could be helped with sunlight."

 

Learn more about Seasonal Affective Disorder (SAD) in Healia Communities.

 The air quality in and around your home may have negative effects on your child’s intelligence, according to a study by Columbia University Center for Children’s Environmental Health (CCCEH).

The study, released a week ago by the National Institute of Environmental Health Sciences (NIEHS), found that children exposed to chemical pollutants called polycyclic aromatic hydrocarbons found in the air, water, and soil scored lower on IQ tests than children with lower exposure.

Polycyclic aromatic hydrocarbons, or PAHs, are chemical pollutants that can be found in the air, water, and soil. PAHs are typically released from the burning of fossil fuels (coal, diesel, oil, gas, etc.), tobacco and other natural substances. Auto emissions are a major source of PAHs in the United States, especially in heavily trafficked urban areas.

Doctor Frederica Perera, lead author and professor of Environmental Health Sciences at Columbia University Mailman School of Public Health, compares the exposure to such pollutants to low-level lead exposure. “These findings are of concern because these decreases in IQ could be educationally meaningful in terms of school performance,” she says. “IQ is an important predictor of future academic performance.”

A child’s developing fetal and nervous system is more vulnerable than an adult’s, and PAHs have been associated with higher cancer risk, asthma, allergies, low birth weight, and a reduced head circumference. Reduced head circumference, according to CCCEH, is connected with lower cognitive functioning and academic performance. In this study, the first of its kind, researchers hoped to study the relationship of in utero PAH exposure on a child’s intelligence.
 
Participants were non-smoking black and Dominican-American women, aged 18-35, residing in Washington Heights, Harlem and South Bronx, N.Y.—areas with higher pollutant exposure. During pregnancy participants regularly completed questionnaires and were asked to wear monitors that measured PAH levels.

Researchers followed the children, measuring IQ levels at age three and again at age five using the Wechsler Preschool and Primary Scale of the Intelligence. Of the 249 children, 140 had higher than the average 2.26 n/m3 level of exposure. The mean score for all children was 98.72, with a mean score of 96.6 for children whose exposure was classified as “high” and 101.6 for children with lower exposure. Scores differed by 4.67 on the verbal and 4.31 points on the full-scale test.

Researchers will continue to follow children to age 11 to learn more about the effects of PAHs on intelligence and child development. “It should serve as a warning bell to us all,” says Linda Birnbaum, Ph.D., director of NIEHS. “We need to do more to prevent environmental exposures from harming our children.”

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The U.S. Centers for Disease Control and Prevention (CDC) released a report today showing that more than 86,000 people are injured each year in falls caused by their cats and dogs, for an average annual injury rate of 29.7 per 100,000 people. Most of the injuries caused by pets were minor, but nearly 10 percent were serious enough to require hospitalization.

CDC researchers examined records from the emergency departments at 66 U.S. hospitals for the years 2001 through 2006 looking for mentions of dogs and cats involved in nonfatal injuries. According to the report, injuries related to falls caused by pets have never really been examined.

The results of the study show that nearly 88% of injuries caused by pet-related falls were associated with dogs, and females were 2.1 times more likely to be injured than males. Senior citizens were also disproportionately affected, with the rate of pet-related injuries nearly twice as high for people 75 and older. Overall, falls caused by pets account for only about one percent of all injuries from falls.

Nearly 62 percent of dog-related injuries occurred inside or immediately outside the home. Thirty-one percent of those cases involved falling or tripping over a dog. Other common dog-related falls occurred when someone was startled, pushed or pulled off balance during a walk, or fell down while chasing after a runaway dog.

Most falls involving cats occurred at home, with 66 percent due to the person falling or tripping over the cat. This will come as no surprise to cat owners, who may feel like their cat it is always underfoot.

The CDC released the report to educate the public on the dangers of such injuries and to suggest strategies for prevention. According to the report, such strategies should focus on increasing public awareness of pets and pet items as fall hazards and reinforcing American Veterinary Medical Association recommendations emphasizing obedience training for dogs.

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_{Photo: Mr. T in DC, Flickr, Creative Commons}

A study released this week by Baylor University shows that fish caught in five rivers across the U.S. harbor low-levels of several pharmaceuticals, including drugs that lower cholesterol levels, antidepressants, anti-convulsants, and drugs that treat allergies, high blood pressure, and bipolar disorder. The study was the first to examine the levels of pharmaceuticals in freshwater fish on a national scale.

Researchers took fish from rivers in Chicago, Dallas, Orlando, Phoenix, and Philadelphia, all of which collect the outflow from wastewater treatment plants. For comparison, they also tested fish from a river in New Mexico that is unaffected by human pollution.

Scientists tested the fish for the presence of 24 different pharmaceuticals and 12 chemicals found in beauty products. They found trace amounts of seven pharmaceuticals and two chemicals form beauty products in fish at all five river sites. The drugs included gemfibrozil, diphenhydramine, carbamazepine, norfluoxetine, fluoxetine and sertraline. The chemicals they found were galaxolide and tonalide, which are fragrances used in soap and other beauty products. None of the drugs or chemicals were found at the New Mexico river site.

While the amounts of the drugs found in the fish were very low – hundreds of thousands of times less than a therapeutic dose – what has the researchers and the Environmental Protection Agency (EPA) concerned is the effects of long-term consumption of trace amounts of medicines, especially in unknown combinations. Some evidence suggests that combinations of these pharmaceuticals, even in small amounts, could have a negative effect on the growth of human cells.

It is likely that fish absorb the pharmaceuticals because the rivers they live in are contaminated with traces of drugs that are not removed in wastewater treatment plants. Most of the drugs come from the un-metabolized byproducts of pharmaceuticals that people have taken and then excreted, while a smaller amount comes from unused drugs dumped down the drain.

A year ago, a separate study found trace amounts of pharmaceuticals in the drinking water of several major metropolitan areas.

For more information on chemical pollution, join the Healia Online Community for Environmental Health.

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