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Monthly Archives: February 2017

Global Warming May Pose Health Risks

Medical and public health groups are banding together to explain how global warming has taken a toll on human health and will continue to cause food-borne illnesses, respiratory problems, and deaths unless policy changes are enacted.

In a conference call with reporters, the heads of the American Medical Association (AMA) and the American Public Health Association (APHA) joined with a pediatrician and a scientist to lay out what they say is a major public health issue: climate change caused by global warming.

The “evidence has only grown stronger” that climate change is responsible for an increasing number of health ills, including asthma, diarrheal disease, and even deaths from extreme weather such as heat waves, said Dr. Georges Benjamin, executive director of the APHA.

For one, rising temperatures can mean more smog, which makes children with asthma sicker, explained pediatrician Dr. Perry Sheffield, assistant professor in the Department of Pediatrics and the Department of Preventive Medicine at the Mount Sinai School of Medicine, in New York.

There is also evidence that pollen season is also getting longer, she said, which could lead to an increase in the number of people with asthma.

Climate change also is thought to lead to increased concentrations of ozone, a pollutant formed on clear, cloudless days. Ozone is a lung irritant which can affect asthmatics, those with chronic obstructive pulmonary disease, and those with heart disease, said Dr. Kristie Ebi, who is a member of the Intergovernmental Panel on Climate Change.

More ozone can mean more health problems and more hospital visits, she said.

Aside from air-related ailments and illnesses, extreme weather can have a devastating effect on health, Sheffield said.

“As a result of global warming, extreme storms including hurricanes, heavy rainfall, and even snowstorms are expected to increase,” Sheffield said. “And these events pose risk of injury and disruption of special medical services, which are particularly important to children with special medical needs.”

Extreme heat waves and droughts are responsible for more deaths than any other weather-related event, Sheffield said.

The 2006 heat wave that spread through most of the U.S. and Canada saw temperatures that topped 100 degrees. In all, 450 people died, 16,000 visited the emergency room, and 1,000 were hospitalized, said Dr. Cecil Wilson, president of the AMA.

Climate change has already caused temperatures to rise and precipitation to increase, which, in turn, can cause diseases carried by tics, mosquitoes, and other animals to spread past their normal geographical range, explained Ebi.

For instance, Lyme disease is increasing in some areas, she said, including in Canada, where scientists are tracking the spread of Lyme disease north.

Ebi also recounted the 2004 outbreak of the leading seafood-related cause of gastroenteritis, Vibrio parahaemolyticus, from Alaskan seafood, which was attributed to increased ocean temperatures causing infected sea creatures to travel 600 miles north.

Salmonella outbreaks also increase when temperatures are very warm, Sheffield said.

A 2008 study also projected that global warming will lead to a possible increase in the prevalence of kidney stones due to increased dehydration, although the link hasn’t been proven.

Wilson said the AMA wants to make doctors aware of the projected rise in climate-related illnesses. To combat climate change, Wilson says physicians and public health groups can advocate for policies that improve public health, and should also serve as role models by adopting environmentally-friendly policies such as eliminating paper waste and using energy-efficient lighting in their practices.

“Climate instability threatens our health and life-supporting system, and the risk to our health and well-being will continue to mount unless we all do our part to stabilize the climate and protect the nation’s health,” said Wilson.

Benjamin added that doctors should pay attention to the Air Quality Index. For instance, if there’s a “Code Red” day, which indicates the air is unhealthy, physicians should advise patients (particularly those with cardiac or respiratory conditions) that it’s not the day to try and mow the grass.

“ER docs are quite aware of Code Red days because we know that when those occur, we’re going to see lots of patients in the emergency room,” Benjamin said.

The conference call came as Congress is considering what role the Environmental Protection Agency (EPA) should have in updating its safeguards against carbon dioxide and other pollutants.

While the EPA has the authority to regulate levels of CO2, a budget bill passed by the House of Representatives last the weekend prohibited the EPA from exercising that authority. Meanwhile, other bills are pending in Congress that would significantly delay the agency’s ability to regulate air pollutants.

AMA has a number of policies on the books regarding climate change, including a resolution supporting the EPA’s authority to regulate the control of greenhouse gases, and a statement endorsing findings from the most recent Intergovernmental Panel on Climate Change report that concludes the Earth is undergoing adverse climate changes, and that humans are a significant contributor to the changing weather.

In that statement, the AMA said it supports educating the medical community about climate change and its health implications through medical education on topics such as “population displacement, heat waves and drought, flooding, infectious and vector-borne diseases, and potable water supplies.”

The statement also said the AMA supports physician involvement in policymaking to “search for novel, comprehensive, and economically sensitive approaches to mitigating climate change to protect the health of the public.”

Medical Leech Linked to Infection

A resistant Aeromonas infection transmitted by a medicinal leech developed in a man undergoing reconstructive surgery of the jaw, leading to total failure of the graft, investigators reported.

“Leech therapy is the most effective nonsurgical management of soft-tissue venous congestion,” explained Dr. Brian Nussenbaum, of Washington University School of Medicine in St. Louis, and colleagues.

However, because a bug — Aeromonas hydrophila — lives in the gut of leeches where this bacteria aids in the digestion of blood, infections can occur in as many as 20 percent of patients treated with medical leeches, according to a report in the February Archives of Otolaryngology-Head and Neck Surgery.

So to prevent infection, researchers are recommending that when medical leeches are used, patients should be given antibiotics, preferably Cipro (ciprofloxacin) or Septra (trimethoprim-sulfamethoxazole).

The patient was a 56-year-old man undergoing a reconstructive procedure for a large benign tumor in his jaw. He was given ampicillin-sulbactam as prophylaxis.

Approximately 24 hours after the surgery, he developed a condition called acute venous congestion, meaning a lack of blood supply that turns skin and tissue blue, in the area of the surgery.

In preparation for revision of the surgery, which revealed widespread clot formation, the patient was given 400 mg of intravenous ciprofloxacin and three leeches were applied to the area.

The surgery appeared to have been successful, but despite maintenance therapy with ciprofloxacin, 48 hours later purulent secretions appeared, and cultures with sensitivity testing identified a strain of A. hydrophila that was resistant to both trimethoprim-sulfamethoxazole and ciprofloxacin.

Ciprofloxacin was withdrawn and the fourth-generation cephalosporin, cefepime, was prescribed.

The wound did not heal completely and eight months later the patient required a second reconstruction eight months later.

To determine the source of this resistant infection, Nussenbaum’s group conducted a two-part investigation.

First, to see if the infection was acquired within their hospital, they performed cultures on samples of water from their leech tank — and found that all samples were susceptible to multiple antimicrobials, including ciprofloxacin and trimethoprim-sulfamethoxazole.

They also noted that no other resistant Aeromonas infections had been seen at their institution.

“This practice-based investigation suggests that this strain was not acquired within our hospital,” they stated.

They then conducted a broader investigation, contacting various organizations including the Centers for Disease Control and Prevention and the Emerging Infections Network, finding that no other cases of similar resistant infections associated with medical leeches had been reported.

The leech supplier also reported careful maintenance of holding tanks, although antibiotic resistance tests were not routinely done.

The investigators found, however, that ciprofloxacin-resistant strains of Aeromonashad been identified from environmental sources such as drinking water in Turkey, a lake in Switzerland, and the Seine River.

These isolates contained a plasmid encoding fluoroquinolone resistance, which had previously only been found in Enterobacteriaceae.

“These findings suggest the possibility of emerging ciprofloxacin resistance in environmental water supplies, which is concerning,” observed Nussenbaum and colleagues.

Limitations of the study included the investigators’ inability to culture the gut contents of other leeches from the same batch, and the lack of specimens that could be tested for the presence of the resistance-conferring plasmid.

The study suggests that, although resistance to trimethoprim-sulfamethoxazole and ciprofloxacin is rare in A. hydrophila, it can occur and should be considered when antibiotic prophylaxis is undertaken, according to the investigators.

“Surgeons using leech therapy should be aware of this possibility and collaborate with infectious disease specialists in their hospital to determine appropriate antibiotic prophylaxis on local resistance patterns,” they cautioned.

Chemical Found in Blood Holds Clues to Survival

Even within the normal range, higher bilirubin levels appear to be associated with reduced risks of lung cancer, chronic obstructive pulmonary disease (COPD), and death, a longitudinal, prospective analysis of a large database showed.

For every 0.1-mg/dL increase in bilirubin level, the rate of lung cancer dropped by 8 percent in men and 11 percent in women, according to Laura Horsfall, MSc, of University College London, and colleagues.

In addition, the same incremental increase in bilirubin was associated with a 6 percent decline in the rate of COPD and a 3 percent decline in mortality for both sexes, the researchers reported in the Feb. 16 issue of the Journal of the American Medical Association.

“Based on our findings, bilirubin levels within the normal range appear to capture information about patients that may reflect a combination of environmental and genetically determined susceptibility to respiratory diseases,” they wrote.

Most people are familiar with bilirubin because of its role in jaundice — the yellowing of the skin that is sometimes seen in newborns but is also associated with liver disease.

Bilirubin is actually a byproduct of the turn over of red blood cells — the cells that carry oxygen throughout the body. Healthy individuals constantly replace old red blood cells with new ones. As the old cells are broken down they produce bilirubin, a chemical characterized by a distinctive yellow color.

The spleen and the liver taking in bilirubin and use it to break down or metabolize other substances into bile, which is used to aid digestion.

Although the study cannot establish causality for any of the relationships, there is some experimental evidence that bilirubin has benefits for respiratory health because of its cytoprotective properties, including antioxidant, anti-inflammatory, and antiproliferative effects, according to the researchers.

They noted that a better understanding of the possible mechanisms linking bilirubin levels to lung cancer, COPD, and death may lead to potential therapies that target the activity of UGT1A1, a liver enzyme responsible for converting insoluble bilirubin to an excretable form.

Horsfall and her colleagues examined data from the Health Improvement Network, a U.K. primary care research database.

Their analysis included 504,206 patients ages 20 and older from 371 practices. All of the patients had recorded serum bilirubin levels but no evidence of hepatobiliary or hemolytic disease.

Median bilirubin levels were 0.64 mg/dL in men and 0.53 mg/dL in women.

Through a median follow-up of eight years, there were 1,341 incident cases of lung cancer, 5,863 incident cases of COPD, and 23,103 all-cause deaths. The corresponding rates per 10,000 person-years were 2.5, 11.9, and 42.5.

For men, the rate of lung cancer per 10,000 person-years dropped from 5.0 in the lowest decile of bilirubin levels to 3.0 in the fifth decile. Similar declines were seen for COPD (19.5 to 14.4) and death (51.3 to 38.1).

The findings were similar for all outcomes in women, and the declines in both sexes remained significant after adjustment for age, body mass index, systolic blood pressure, smoking, alcohol intake, and a measure of social deprivation.

The authors acknowledged some limitations of the study, including possible residual confounding by unmeasured environmental exposures or race/ethnicity and the inability to establish causality for the observed relationships.

Marijuana Users at Risk for Early Psychosis

Data on more than 22,000 patients with psychosis showed an onset of symptoms almost three years earlier among users of cannabis compared with patients who had no history of substance use.

The age of onset also was earlier in cannabis users compared with patients in the more broadly characterized category of substance use, investigators reported online in Archives of General Psychiatry.

“The results of this study provide strong evidence that reducing cannabis use could delay or even prevent some cases of psychosis,” Dr. Matthew Large, of the University of New South Wales in Sydney, Australia, and co-authors wrote in conclusion.

“Reducing the use of cannabis could be one of the few ways of altering the outcome of the illness because earlier onset of schizophrenia is associated with a worse prognosis and because other factors associated with age at onset, such as family history and sex, cannot be changed.”

Psychosis has a strong association with substance use. Patients of mental health facilities have a high prevalence of substance use, which also is more common in patients with schizophrenia compared with the general population, the authors wrote.

Several birth cohort and population studies have suggested a potentially causal association between cannabis use and psychosis, and cannabis use has been linked to earlier onset of schizophrenia. However, researchers in the field remain divided over the issue of a causal association, the authors continued.

Attempts to confirm an earlier onset of psychosis among cannabis users have been complicated by individual studies’ variation in methods used to examine the association. The authors sought to resolve some of the uncertainty by means of meta-analysis.

A systematic search of multiple electronic databases yielded 443 potentially relevant publications. The authors whittled the list down to 83 that met their inclusion criteria: All the studies reported age at onset of psychosis among substance users and nonusers.

The studies comprised 8,167 substance-using patients and 14,352 patients who had no history of substance use. Although the studies had a wide range of definitions of substance use, the use was considered “clinically significant” in all 83 studies. None of the studies included tobacco in the definition of substance use.

The studies included a total of 131 patient samples.

Substance use included alcohol in 22 samples, cannabis in 41, and was simply defined as “substance use” in 68 samples.

Alcohol use was not significantly associated with earlier age at onset of psychosis.

On average, substance users were about 2 years younger than nonusers were. The effect of substance use on age at onset was greater in women than in men, but not significantly so. Heavy use was associated with earlier age at onset compared with light use and former use, but also not significantly different, the authors reported.

Substance users were two years younger at the onset of psychosis compared with nonusers. Age at onset was 2.7 years earlier among cannabis users compared with nonusers.

Acknowledging limitations of the study, the authors cited the lack of information on tobacco use and its association with earlier age at onset of psychosis, and the lack of data on individual patients inherent in all meta-analyses.

Despite the limitations, the authors said the findings have potentially major clinical and policy implications.

“This finding is an important breakthrough in our understanding of the relationship between cannabis use and psychosis,” they wrote in conclusion. “It raises the question of whether those substance users would still have gone on to develop psychosis a few years later.”

“The results of this study confirm the need for a renewed public health warning about the potential for cannabis use to bring on psychotic illness,” they added.