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Drawing of colon seen from front (appendix is colored red). Credit: Wikipedia

This is the second time I've seen research finding that antibiotics  alone could be used (instead of surgery) for the treatment of uncomplicated appendicitis (June 17, 2015 post), but this time in children. Appendicitis is inflammation of the appendix.  At the one year follow-up the researchers found that 75.7% of patients with uncomplicated appendicitis had been successfully treated with antibiotics alone and had not had any recurrences of appendicitis.

This is a major finding because for years the gold standard for appendicitis treatment has been an appendectomy. The times are a changing.

From Science Daily: Antibiotics alone can be a safe, effective treatment for children with appendicitis

Using antibiotics alone to treat children with uncomplicated acute appendicitis is a reasonable alternative to surgery when chosen by the family. A study led by researchers at Nationwide Children's Hospital found that three out of four children with uncomplicated appendicitis have been successfully treated with antibiotics alone at one year follow-up. Compared to urgent appendectomy, non-operative management was associated with less recovery time, lower health costs and no difference in the rate of complications at one year.

"Surgery has long been the 'gold standard' of care for treating appendicitis because by removing the appendix we eliminate the chance that the appendicitis will ever come back," said Dr. Deans. "However, early in our careers we noticed that patients with appendicitis who were placed on antibiotics overnight until their surgery the following morning felt better the next day. So, Pete and I asked ourselves: do they really need to have surgery?"

In the first study conducted and published in the United States examining non-operative management for appendicitis, they enrolled 102 patients age 7 to 17 who were diagnosed with uncomplicated acute appendicitis at Nationwide Children's between October 2012 and October 2013. Participants had early/mild appendicitis, meaning that they experienced abdominal pain for no more than 48 hours; had a white blood cell count below 18,000; underwent an ultrasound or CT scan to rule out rupture and to verify that their appendix was 1.1 centimeter thick or smaller; and had no evidence of an abscess or fecalith, which is hard stone-like piece of stool.

Thirty-seven families chose antibiotics alone and 65 opted for surgery. Those patients in the non-operative group were admitted to the hospital and received IV antibiotics for at least 24 hours, followed by oral antibiotics after discharge for a total of 10 days. Among those patients, 95% showed improvement within 24 hours and were discharged without undergoing surgery. Rates of appendicitis-related medical care within 30 days were similar between the groups with two patients in the non-operative group readmitted within 30 days for an appendectomy. At one year after discharge, three out of four patients in the non-operative group did not have appendicitis again and have not undergone surgery.

Appendicitis, caused by a bacterial infection in the appendix, is the most common reason for emergency abdominal surgery in children, sending more than 70,000 young people to the operating room each year. Although many of these cases are severe and require surgery, there are a good number that would be candidates for treatment with antibiotics alone, Dr. Minneci said.

According to the study results, patients who were transferred to Nationwide Children's from other institutions expressed concerns about the distance and time necessary to come back if the appendicitis recurred. These families opted for surgery more often. Patients whose families spoke primary languages other than English were more likely to choose antibiotics as a course of treatment due to cultural values to avoid surgery if at all possible.

Recent research looked at environmental causes of male infertility, specifically endocrine-disrupting chemicals. Poor semen quality contributes to increases in infertility and the use of assisted reproductive technology.The researchers also discuss the higher incidence of testicular cancer worldwide, lower levels of testosterone in men, and poor semen quality among men aged 20 to 25 (with the average man having up to 90% abnormal sperm). From Science Daily:

Endocrine-disrupting chemicals may be threatening fertility in industrialized countries

The birth rate is declining in all industrialised countries, and socioeconomic factors and women's age are not solely to blame. Male reproductive health and environmental factors are also significant, as concluded in a new scientific review article. ...Behind the article are fertility researchers from Denmark, the US and Finland. The researchers studied a number of factors related to fertility, and one of the main conclusions of their study was that poor semen quality contributed to increases in infertility and the use of assisted reproductive technology.

The study also revealed higher incidence of testicular cancer worldwide, with the greatest frequency among Caucasian populations. Moreover, the researchers also observed lower levels of testosterone in average men. "I was surprised that we found such poor semen quality among young men aged 20 to 25. The average man had up to 90% of abnormal sperm. Normally, there would be so many sperms that a few abnormal ones would not affect fertility. However, it appears that we are at a tipping point in industrialised countries where poor semen quality is so widespread that we must suspect that it results in low pregnancy rates," said first author of the article, Professor Niels E. Skakkebaek from the Department of Growth and Reproduction (EDMaRC) at Rigshospitalet and the University of Copenhagen.

"The article also demonstrates the impact of the increasing number of male reproductive problems on low birth rates. There is no doubt that environmental factors are playing a role. These are the correlations we are researching at the new research centre EDMaRC at Rigshospitalet," added Professor Anders Juul, who is the last author of the article.

Many of the male reproductive problems could be due to damage to the testes during embryonic development. While the reproductive problems could arise from genetic changes, "recent evidence suggests that most often they are related to environmental exposures of the fetal testes," the researcher team wrote."Since the disorders in male genitals have increased over a relatively short period of time, genetics alone cannot explain this development. There is no doubt that environmental factors are playing a role and that endocrine-disrupting chemicals, which have the same effect on animals, are under great suspicion. The exposure that young people are subjected to today can determine not only their own, but also their children's, ability to procreate," explained Professor Skakkebaek.

A recent study found that men with infertility have a much higher risk for a variety of other chronic medical conditions, including diabetes, heart disease, renal disease, alcohol abuse, and drug abuse. Thus, it appears that male infertility may be a symptom or a clue that there may be other health problems. One example is that male infertility is linked to an 81% greater risk of diabetes, and the greatest risk for renal disease occurred among men with azoospermia (zero sperm counts, the most severe form of male infertility). From Medscape:

Infertility in Men Tied to Heart Disease, Chronic Conditions

Men with infertility have a higher risk for a variety of other chronic medical conditions, including diabetes, heart disease, alcohol abuse, and drug abuse, according to a retrospective cohort study published online December 7 in Fertility and Sterility."The results suggest that male factor infertility has more than just reproductive implications," write Michael Eisenberg, MD, assistant professor of urology and director of male reproductive medicine and surgery at Stanford University School of Medicine in California, and colleagues.

The researchers used insurance claims data from 2001 to 2008 from the Truven Health MarketScan to identify more than 115,000 patients for the study population. They compared outcomes among 13,027 men diagnosed with male factor infertility (average age, 33 years), with outcomes among 23,860 men (average age, 33 years) who received semen or infertility testing and with outcomes among 79,099 men who had received vasectomies.

The authors looked for 16 conditions: hypertension, diabetes, hyperlipidemia, renal disease, chronic pulmonary disease, liver disease, depression, peripheral vascular disease, cerebrovascular disease, ischemic heart disease, other heart disease, injury, alcohol abuse, drug abuse, anxiety disorders, and bipolar disorder.

The men with infertility had higher rates of obesity and smoking, but even after adjustment for these covariates and for age, follow-up time, and healthcare use, men with infertility had a higher risk for multiple conditions compared with vasectomized men or those receiving only fertility testing. Specifically, compared with the men who received fertility testing, men with infertility had a 30% increased risk for diabetes (hazard ratio [HR], 1.30; 95% confidence interval [CI], 1.10 - 1.53), a 48% increased risk for ischemic heart disease (HR, 1.48; 95% CI, 1.19 - 1.84) and for alcohol abuse (95% CI, 1.07 - 2.05), a 67% increased risk for drug abuse (HR, 1.67; 95% CI, 1.06 - 2.63), and a 19% increased risk for depression (HR, 1.19; 95% CI, 1.04 - 1.36).

Compared with men who received vasectomies, those with infertility had a 9% higher risk for hypertension (HR, 1.09; 95% CI, 1.02 - 1.17), a 14% greater risk for hyperlipidemia (HR, 1.14; 95% CI, 1.07 - 1.22), a 41% greater risk for ischemic heart disease (HR, 1.41; 95% CI, 1.19-1.67), and a 16% greater risk for other heart disease (HR, 1.16; 95% CI, 1.04 - 1.29). Further, men with infertility, compared with vasectomized men, had an 81% greater risk for diabetes (HR, 1.81; 95% CI, 1.57 - 2.08), a 60% greater risk for renal disease (HR, 1.60; 95% CI, 1.14 - 2.24), a 53% greater risk for liver disease (HR, 1.53; 95% CI, 1.31 - 1.80), and a 52% greater risk for peripheral vascular disorders (HR, 1.52; 95% CI, 1.12 - 2.07).

Of course! Makes sense that people who have a higher sense of purpose in life are at lower risk of death and cardiovascular disease!. From Science Daily:

Sense of purpose in life linked to lower mortality and cardiovascular risk

People who have a higher sense of purpose in life are at lower risk of death and cardiovascular disease, reports a pooled data analysis."Possessing a high sense of purpose in life is associated with a reduced risk for mortality and cardiovascular events," according to the study by Drs. Randy Cohen and Alan Rozanski and colleagues at Mt. Sinai St. Luke's-Roosevelt Hospital, New York. While the mechanisms behind the association remain unclear, the findings suggest that approaches to strengthening a sense of purpose might lead to improved health outcomes.

Using a technique called meta-analysis, the researchers pooled data from previous studies evaluating the relationship between purpose in life and the risk of death or cardiovascular disease. The analysis included data on more than 136,000 participants from ten studies -- mainly from the United States or Japan. The US studies evaluated a sense of purpose or meaning in life, or "usefulness to others." The Japanese studies assessed the concept of ikigai, translated as "a life worth living."

The study participants, average age 67 years, were followed up for an average of seven years. During this time, more than 14,500 participants died from any cause while more than 4,000 suffered cardiovascular events (heart attack, stroke, etc).

The analysis showed a lower risk of death for participants with a high sense of purpose in life. After adjusting for other factors, mortality was about one-fifth lower for participants reporting a strong sense of purpose, or ikigai. A high sense of purpose in life was also related to a lower risk of cardiovascular events. Both associations remained significant on analysis of various subgroups, including country, how purpose in life was measured, and whether the studies included participants with pre-existing cardiovascular disease..

There is a well-documented link between "negative psychosocial risk factors" and adverse health outcomes, including heart attack, stroke, and overall mortality. "Conversely, more recent study provides evidence that positive psychosocial factors can promote healthy physiological functioning and greater longevity," according to the authors.

While further studies are needed to determine how purpose in life might promote health and deter disease, preliminary data suggest a few basic mechanisms. The association might be explained physiologically, such as by buffering of bodily responses to stress; or behaviorally, such as by a healthier lifestyle.

It seems that a lot has been written about the health benefits of some berries, such as blueberries, while other berries have been neglected. This study focused on red raspberries, black raspberries, and blackberries. While the study was done in Poland, it was pointed out that these berries are also commonly grown in the USA. Red raspberry, black raspberry, and blackberry fruits are abundant in dietary phytochemicals such as flavonols, phenolic acids, ellagitannins, vitamins C and E, folic acid, and β-sitosterol. Many of these bioactive compounds exhibit antioxidant activity. Anthocyanins and other phenolic compounds such as ellagitannins and ellagic acid, which distinguish raspberry from other berries, occur in high levels and are mainly responsible for their broad beneficial health properties (including anti-inflammatory, antimicrobial, and antiviral activities).

For these reasons, the researchers said that "raspberry and blackberry fruits can be regarded as natural functional foods". Another term for functional foods is nutraceutical, which is a food containing health-giving additives and having medicinal benefit. From Science Daily:

Looking for the best antioxidant fruit? Search no further than black raspberries

As far as healthy foods go, berries make the top of the list. They contain potent antioxidants, which decrease or reverse the effects of free radicals -- natural byproducts of energy production that can play havoc on the body and that are closely linked with heart disease, cancer, arthritis, stroke or respiratory diseases.

Unsurprisingly, the benefits of berries are extoled in one study after another....The research published now in Open Chemistry suggests that black raspberries grown in Central Europe show greater health benefits than their better known cousins -- raspberries or blackberries.

A group of researchers led by Anna Małgorzata Kostecka-Gugała measured the content of phenolics and anthocyanins in black raspberries, red raspberries and blackberries, assessing their antioxidant potential and health benefits. They were able to confirm that the antioxidant activity of natural products correlates directly with their health promoting properties.

It turns out that the amount of antioxidants in black raspberries was three times higher than the other fruits under investigation. Remarkably, the number was even higher for phenolics or the amount of anthocyanines -- with black raspberries topping their humble cousins by over 1000%. But most interestingly, black raspberries seem to be characterized by a higher content of secondary metabolites, which have been proved beneficial for human health.

New research showed that eight days after a concussion, the concussed athletes (football players) looked and felt like they had recovered (clinical recovery), but MRIs showed that there were still neurophysiological abnormalities (significant blood flow decrease) in their brains. They did not look at if and when the blood flow returned to normal, but that research also needs to be done.

It is very disturbing to look at both this research and also the finding that the off-season is not enough for high school football players to recover from the repeated hits (not concussions, but sub-concussive hits) that they receive during the football season (Nov. 24, 2015 post). Do student football players really know and understand the dangers to their brains from the repeated hits and also concussions that occur in football? From Medical Xpress:

Reduced blood flow seen in brain after clinical recovery of acute concussion

Some athletes who experience sports-related concussions have reduced blood flow in parts of their brains even after clinical recovery, according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA). The results suggest a role for MRI in determining when to allow concussed athletes to return to competition.

Decisions to clear concussed athletes to return to action are typically based on symptoms and cognitive and neurological test results. However, there is increasing evidence that brain abnormalities persist beyond the point of clinical recovery after injury. To find out more, researchers from the Medical College of Wisconsin in Milwaukee studied concussed football players with arterial spin labeling, an advanced MRI method that detects blood flow in the brain.

Dr. Wang and colleagues studied 18 concussed players and 19 non-concussed players. They obtained MRI of the concussed players within 24 hours of the injury and a follow-up MRI eight days after the injury and compared results with those of the non-concussed players. Clinical assessments were obtained for both groups at each time point, as well as at the baseline before the football season.

The concussed players demonstrated significant impairment on clinical assessment at 24 hours post-injury, but returned to baseline levels at eight days. In contrast to clinical manifestation, the concussed players demonstrated a significant blood flow decrease at eight days relative to 24 hours post-injury, while the non-concussed players had no change in cerebral blood flow between the two time points.

"In eight days, the concussed athletes showed clinical recovery," Dr. Wang said. "However, MRI showed that even those in clinical recovery still had neurophysiological abnormalities. Neurons under such a state of physiologic stress function abnormally and may become more susceptible to second injury." "For years, we've relied on what athletes are telling us," Dr. McCrea said. "We need something more objective, and this technology may provide a greater measurement of recovery."

Loneliness or social isolation is a health risk that can increase the risk of chronic illness and premature death. Why?  Loneliness leads to fight-or-flight stress signaling, which can ultimately affect the production of white blood cells. Essentially, lonely people had a less effective immune response and more inflammation than non-lonely people. The study was part of the Chicago Health, Aging, and Social Relations Study (CHASRS) and followed 144 people over 10 years. From Science Daily:

Loneliness triggers cellular changes that can cause illness, study shows

Loneliness is more than a feeling: For older adults, perceived social isolation is a major health risk that can increase the risk of premature death by 14 percent.

Now a team of researchers, including U Chicago psychologist and leading loneliness expert John Cacioppo, has released a study shedding new light on how loneliness triggers physiological responses that can ultimately make us sick. The paper.... shows that loneliness leads to fight-or-flight stress signaling, which can ultimately affect the production of white blood cells. The study examined loneliness in both humans and rhesus macaques, a highly social primate species.

Previous research from this group had identified a link between loneliness and a phenomenon they called "conserved transcriptional response to adversity" or CTRA. This response is characterized by an increased expression of genes involved in inflammation and a decreased expression of genes involved in antiviral responses. Essentially, lonely people had a less effective immune response and more inflammation than non-lonely people.

For the current study, the team examined gene expression in leukocytes, cells of the immune system that are involved in protecting the body against bacteria and viruses. As expected, the leukocytes of lonely humans and macaques showed the effects of CTRA--an increased expression of genes involved in inflammation and a decreased expression of genes involved in antiviral responses. But the study also revealed several important new pieces of information about loneliness' effect on the body.

Next, the team investigated the cellular processes linking social experience to CTRA gene expression in rhesus macaque monkeys at the California National Primate Research Center, which had been behaviorally classified as high in perceived social isolation. Like the lonely humans, the "lonely like" monkeys showed higher CTRA activity. They also showed higher levels of the fight-or-flight neurotransmitter, norepinephrine.

Previous research has found that norepinephrine can stimulate blood stem cells in bone marrow to make more of a particular kind of immune cell--an immature monocyte that shows high levels of inflammatory gene expression and low levels of antiviral gene expression. Both lonely humans and "lonely like" monkeys showed higher levels of monocytes in their blood.

Taken together, these findings support a mechanistic model in which loneliness results in fight-or-flight stress signaling, which increases the production of immature monocytes, leading to up-regulation of inflammatory genes and impaired anti-viral responses. The "danger signals" activated in the brain by loneliness ultimately affect the production of white blood cells. The resulting shift in monocyte output may both propagate loneliness and contribute to its associated health risks.

This past week there was discussion of the number of high school football players that die annually while playing football (at least 5). But the bigger risk - because it involves so many players - is the damage to brains that occurs from concussions and from just being hit in football. The response from football enthusiasts is that there are safeguards now - that football players don't play after a concussion until they "heal" (show no obvious symptoms). But do they really heal? And much of the damage is from repeated hits, without having a concussion (sub-concussive blows or hits), what about the damage from that?

This study found that repeated head hits in football can cause changes in brain chemistry and metabolism, even in high school players not diagnosed with concussions. And even after the lengthy off-season (somewhere between two and five months after the season has ended)—the majority of players are still showing that they had not fully recovered. The researchers also made it clear that 2 weeks is not enough time to heal from a concussion. Scary long-term implications - what is happening to brains that never truly heal from past seasons as the players start playing in the next season? From Futurity:

High School Football: Teen Brains Don't Heal During Offseason

Brain scans of high school football players taken before, during, and after the season raise concerns they don’t fully recover from repeated head hits. The researchers used an imaging technique called proton magnetic resonance spectroscopy (1H MRS) to study the brains of 25 high school football players and compared them to the brains of teenagers involved in non-contact sports. The findings suggest repeated head hits in football can cause changes in brain chemistry and metabolism, even in players not diagnosed with concussions. 

We are seeing damage not just to neurons, but also to the vasculature and glial cells in the brain,” says Eric Nauman, professor of mechanical engineering, basic medical sciences, and biomedical engineering at Purdue University. “I was particularly disturbed that when you get to the offseason—we are looking somewhere between two and five months after the season has ended—the majority of players are still showing that they had not fully recovered.”

The 1H MRS data provide details about the blood flow, metabolism, and chemistry of neurons and glial cells important for brain function. The data also revealed a “hypermetabolic response” during the preseason, as though the brain was trying to heal connections impaired from the previous season. “We found that in the preseason for the football players in our study, one part of the brain would be associating with about 100 other regions, which is much higher than the controls,” says Thomas Talavage,  professor of electrical and computer engineering and biomedical engineering and co-director of the Purdue MRI Facility.

“The brain is pretty amazing at covering up a lot of changes. Some of these kids have no outward symptoms, but we can see their brains have rewired themselves to skip around the parts that are affected.”

One of the research papers shows that knowing a player’s history of specific types of hits to the head makes it possible to accurately predict “deviant brain metabolism,” suggesting that sub-concussive blows can produce biochemical changes and potentially lead to neurological problems, which indicates a correlation between players taking the heaviest hits and brain chemistry changes.

The data shows that the neurons in the motor cortex region in the brains of football players produced about 50 percent less of the neurotransmitter glutamine compared to controls. “We are finding that the more hits you take, the more you change your brain chemistry, the more you change your brain’s ability to move blood to the right locations,” Nauman says.

“Recent proton magnetic resonance spectroscopy studies argue that the recommended two-week window of rest is insufficient for full metabolic recovery after concussion,” Nauman says. “Those returning to play prior to full recovery could incur a second concussion with symptoms and metabolic changes more lasting than the first.”

Another excellent reason to breastfeed premature infants - to increase the odds of preventing retinopathy of prematurity (ROP), which is the reason preemies can go blind. It occurs when blood vessels in the retinas of premature infants start to grow out of control. If the abnormal growth continues, the retinas detach, and this can cause blindness.

Sadly, an ROP epidemic occurred in the 1940s and early 1950s when hospital nurseries began using excessively high levels of oxygen in incubators to save the lives of premature infants. During this time, ROP was the leading cause of blindness in children in the US. In 1954, scientists funded by the National Institutes of Health determined that the relatively high levels of oxygen routinely given to premature infants at that time were an important risk factor, and that reducing the level of oxygen given to premature babies reduced the incidence of ROP.

Nowadays ROP is a leading cause of childhood blindness in developed countries. A large US study found that in extremely preterm infants with a gestational age of 22 to 28 weeks, the incidence of ROP was 59% (96% at 22 weeks and 32% at 28 weeks). ROP is considered a  multifactorial disease, and risk factors such as prematurity, low birth weight, oxygen therapy, and oxidative stress have been associated with its development.

This recent study was a meta-analysis of five studies (of 2208 pre-term infants), and it found that the overall incidence of ROP was reduced among infants fed human breast milk compared with those fed formula. The best results in preventing severe ROP was in babies fed exclusively breast milk (up to 90% reduction) or mainly human breast milk feeding. It is thought that breast milk may protect against the development of ROP because of its antioxidant and immune-protective properties.  Note that studies involving donor milk were not included because past studies did not find any advantage for donor milk over formula. This may be possibly related to loss of the breast milk microbes (breast milk normally contains up to 700 species of bacteria) during processing (pasteurizing/heat treatment of milk for 30 minutes) and storage of donor milk. From NPR:

Mother's Milk May Help Prevent Blindness In Preemies

If Stevie Wonder had been born three decades later, we might never have gotten "Superstition" and "Isn't She Lovely" — but the musician might never have gone blind, either. Born premature, Wonder developed retinopathy of prematurity, an eye disease that afflicts more than half of babies born before 30 weeks of gestation.Though treatments were developed in the 1980s, about 400 to 600 U.S. children and 50,000 children worldwide still go blind every year from the condition. Now a study suggests that number could be slashed by more than half if all those preemies received their mothers' milk.

The study, actually a combined analysis of five studies from 2001 through 2013, found that preemies receiving human milk from their mothers had 46 to 90 percent lower odds of retinopathy of prematurity (ROP), depending on how much milk they received and how severe the ROP was. The studies were observational, so they cannot show that breast milk directly caused the lower risk.

Of the infants who develop ROP, most recover and develop well without treatment, but about 10 percent develop severe ROP, increasing their risk of blindness, Chiang said. About half of those infants need treatment, which will prevent blindness in 80 to 90 percent of them.

The new research analyzed the outcomes of 2,208 preterm infants based on whether they received exclusive human milk, any human milk, mainly human milk (more than 50 percent), exclusive formula, any formula or mainly formula. The study did not include donor milk, so all the milk was the mother's pumped or hand-expressed breast milk.

Infants who exclusively received breast milk had 89 percent reduced odds of severe ROP compared to infants who received any formula. Infants who received a mixture of breast milk and formula had roughly half the odds of developing severe ROP compared to infants exclusively receiving formula. The analysis included a very large older study that had found no reduced risk for ROP from breast milk, but most infants in that study received less than 20 percent breast milk.

Until the 1940s and 1950s, ROP did not exist because infants born prematurely rarely survived, Chiang said. As doctors learned to how to keep these tiny babies, usually little more than 3 pounds at birth, alive, they discovered that the blood vessels in their retinas would often start to grow out of control. If the abnormal growth continued, their retinas detached, causing blindness.

The cause of ROP isn't entirely understood, but scientists believe oxidative stress can stimulate the abnormal growth of the blood vessels. Providing preemies with oxygen is often key to their survival, but that oxygen exposure might lead to ROP, according to Jianguo Zhou, a neonatologist in Shanghai, and lead author of the study.

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 Several people have recently asked me whether scented candles have any health effects. The answer is a big YES - they have many negative health effects, and so do other scented products such as air fresheners and dryer sheets (e,g, Bounce). All of them contain fragrances and other chemicals - all from petrochemicals (which means they are chemical products derived from petroleum). And yes - all 3 products are totally unnecessary, so ditch them for better health. View all of them as sources of indoor air pollution.

Most of the candles on the market are made with paraffin wax, derived from petroleum, and scented with synthetic fragrances, also derived from petroleum. Synthetic fragrances typically also contain phthalates that can interfere with your hormone system (endocrine disruptors).

In one study scientists at the South Carolina State University lit several brands of candles made of paraffin – the most common and inexpensive candle wax – as well as soy candles (thus vegetable based) and burned them for 5 to 6 hours in a chamber. All of the candles were unscented and undyed. They found that the paraffin candle smoke emits varying levels of pollutants, including benzene, toluene and ketones, as well as hydrocarbon chemicals called alkanes and alkenes, which are components of gasoline. They have been linked to cancer, asthma and birth defects. None of the vegetable-based soy candles produced toxic chemicals. From SC State University:  Frequent use of certain candles produces unwanted chemicals

Researchers point out that the emissions from burning an occasional paraffin candle will not likely cause health problems - it's the frequent lighting of scented paraffin candles in indoor rooms, and inhaling the pollutants in the air that may cause health problems, or as Dr. Massoudi of S. Carolina State University stated: "could contribute to the development of health risks like cancer, common allergies and even asthma."

Scented candles are known to release various volatile organic compounds (VOCs) including both pleasant aromas and toxic components both before lighting (unlit) and when lit. When lit, the "highest emission concentration" was of formaldehyde. By simply touching the candles, one absorbs chemicals through the skin.

Safe candle alternatives are beeswax candles and unscented soy candles. These do not emit toxic chemicals when burned. However, all burning candles emit soot, which is ultrafine, lung-damaging particulate matter that's capable of penetrating deep into the lungs.

From Huffington Post: The Big Problem With Scented Candles

Scented candles are one of the easiest and most effective ways to mask unpleasant odors in your home....But one of the main problems with scented candles is the scent itself. According to Anne Steinemann, an environmental pollutants expert who is a professor of civil engineering and the chair of sustainable cities at the University of Melbourne, certain candles may emit numerous types of potentially hazardous chemicals, such as benzene and toluene. They can cause damage to the brain, lung and central nervous system, as well as cause developmental difficulties.

"I have heard from numerous people who have asthma that they can’t even go into a store if the store sells scented candles, even if they aren’t being burned," Steinemann added. "They emit so much fragrance that they can trigger asthma attacks and even migraines."

Researchers at South Carolina State University tested both petroleum-based paraffin wax candles and vegetable-based candles that were non-scented, non-pigmented and free of dyes. Their 2009 report concluded that while the vegetable-based candles didn't produce any potentially harmful pollutants, the paraffin candles "released unwanted chemicals into the air," said chemistry professor Ruhullah Massoudi in a statement.

It may be shocking to think that your favorite candles could potentially be bad for you, and made worse by added fragrances. Steinemann said for some people, the effects are "immediate, acute and severe," while others may not realize they are being effected until they gradually develop health issues.

Though the risk to you may be small, there are alternatives. Steinemann suggests going the unscented route, avoiding "even those with essential oils, as they can potentially have hazardous chemicals," she said. "It's almost like air fresheners with the fragrance just sitting there ... permeating surfaces in the room."