Posts for category: Environmental Health
Allergies are on the rise! No one has quite figured out all the answers at this point. There’s the “hygiene hypothesis”, which we spoke about previously and other areas of intense on-going research beyond the scope of this post today.
A parent wondered recently and asked if her 13-month old son could be having nasal allergies? My answer was, Yes. This surprised her and this is why. This parent realized and correctly so that you can only respond with allergy-type symptoms to something you’ve been exposed to and subsequently sensitized to. The baby at 13-months old has barely gone through his first allergy season and presumably his very first exposure to the annual tide of environmental allergens (trees, weeds, grasses) and really unlikely to be reacting now, let alone mount an allergic response barely after the first year of exposure.
This parent is factually correct. The development of allergy symptoms often has many factors and is seldom a singular reason. Features of seasonal allergic rhinitis usually do not occur until after the second year of life on the average. A number of exposure cycles are sometimes required before the cascade of body changes which eventually manifest as allergy peak. This 13-month old however was having nasal allergy type symptoms with sneezing, clear runny nose and frequent eye-rubbing not from seasonal “outdoor” allergens - but from perennial “indoor” allergens!
Perennial allergic rhinitis sufferers go through an accelerated cycle of exposure and subsequent sensitization easily due to the ubiquitous nature of the offending allergen in their immediate environment at home usually. The body’s allergy cascade could be sufficiently primed and put in effect within the first year of life. House dust mite, pet/ animal dander, mould, cockroach infested environments are common causes. Airway irritants like cigarette smoke are also harmful to the airway structures and can directly cause injury that may manifest with allergy type symptoms in the early stages.
My patient referenced above lives in an environment where cigarette smoke is present and a number of pet animals are also present in the home. These factors together present poor air quality around this child and have inevitably led to the evolution of allergic rhinitis at a young age. Cat dander is an especially powerful allergen and can be carried by unsuspecting pet cat owners into environments where cat allergy sufferers also hang out. Another patient on our service experienced a situation where sitting close enough to a cat owner at the movies was all it took to get her cat allergy symptoms up.
There is a direct relationship between allergic rhinitis and asthma symptoms. Both conditions tend to reinforce each other and early control with an “all-of-the-above” approach to controlling symptoms with medications and improving the quality of air in the home are often very helpful.Smoking cessation is an important component of the treatment plan. Smoking away outdoors as we often see is welcome. We realize in addition that the cigarette smoke irritants stay on the clothing, hair etc and can still be inhaled by the infant. Smoking cessation helplines are available nationwide and we encourage to avail themselves of the opportunity. I’ve heard of a case though where the family decided to get rid of the Pediatrician rather than the offending pet! - we hope that won’t be the case this time.
The health implications of exposure to nitrates in drinking water were first reported in the scientific literature by Comly in 1945 after observing ashen-gray skin discoloration known as cyanosis in infants in Iowa, where well water was used in formula preparation. Since then, most studies on the health effects of nitrates in drinking water have focused on infants because they are thought to be the most vulnerable to this exposure. More recent evaluations of the health implications of nitrates in drinking water have examined reproductive and developmental effects.
When the delicate balance of nitrogen compounds maintained in nature is tilted by diverse human activities such as fossil fuel combustion, use of nitrogen compounds in fertilizers, and the release of nitrogen in wastewater and the water cycle then the risk of exposure to higher than normal levels in our food or water occurs. The attendant risk of serious health concerns rise accordingly.
Four years after its formation in 1970 the Environmental Protection Agency (EPA) was directed by Congress to monitor the levels of contaminants at which no adverse health effects are likely to occur and acceptable for potable water in our communities called the Safe Drinking Water Act. The maximum contaminant level goals (MCLG) indexed and monitored by the EPA are determined by considering possible health risks from exposure over a lifetime (www.epa.gov). Contaminants monitored are not limited to nitrates and nitrites alone and include any physical, chemical, biological or radiological substances or matter in water. The current standards for acceptable water levels of nitrates are skewed towards what is considered safe for infants.
The potential toxicity of nitrates in contaminated water is enhanced when it occurs or is changed to a peculiar state of combination with oxygen known as nitrite. This form is readily capable of effecting changes with the blood when ingested that make it difficult for the red blood cells to carry out their normal process of oxygen transport and delivery to the tissues. Cumulatively with continued exposure, the amount of red blood cells affected could rise to dangerous levels and cause symptoms affecting different body systems in diverse ways due to oxygen debt and asphyxiation at the cellular level within the body which leads to death without urgent treatment. Newborn infants are especially vulnerable to the effects of nitrites and nitrates. Their body chemistry harbors the conditions necessary for activation of these compounds within the gastrointestinal tract and setting off the cascade. Newborn exposure to higher than normal levels of nitrates and nitrites should be a clinical consideration in the infant with marked irritability without an identifiable cause, or ashen –gray skin discoloration when a credible environmental threat exists. Prompt medical attention should be sought immediately. This condition is known as methemoglobinemia.
The biochemical processes leading to formation of nitrites from ingested nitrates are different in older persons and their body systems offer more resilience and opportunities for detoxification by the body itself. These defense mechanisms in older persons can be overwhelmed when sustained exposure to higher than acceptable levels of nitrates occur. The risk to pregnant mothers has unfortunately been the focus of limited scientific scrutiny. Researchers in Bulgaria (Tabacova et al) in 1997 looked at pregnancy outcomes in a population of mothers selected from areas with high levels of nitrates in their environment and proven higher than acceptable levels of markers of nitrate and nitrite toxicity in body fluids. The results did show adverse outcomes in these pregnancies, however the small size of the population studied and problems factoring the necessary adjustments for confounding variables required by scientific orthodoxy limits the application of their results to general and diverse populations. Experimental animal studies using pigs and laboratory mice on nitrate or nitrite exposure and adverse reproductive and developmental outcomes provide moderate evidence for an association between exposure to nitrate and fetal loss, neonatal mortality, maternal toxicity, and decrease in number of litters and live births. However epidemiologic evidence for increased risk for adverse reproductive and developmental outcomes in humans from exposure to nitrate in drinking water is sparse as mentioned above but has not been completely excluded.
A report published by the CDC in 1996 on a cluster of spontaneous abortions in LaGrange, Indiana, cited nitrate-contaminated water from private wells as the possible cause. The cases included a 35-year-old woman who experienced four consecutive miscarriages and a 37-year-old and a 20-year-old who each experienced one miscarriage. All three women lived within 1 mile of each other and were in the first trimester of pregnancy at the time of the miscarriages. Testing of the wells serving the homes of the women found nitrate to be the only elevated contaminant. The wells had nitrate levels over the MCL (maximum contaminant level) for the three women, respectively. Although these incidents of spontaneous abortion may have been related to the ingestion of nitrate contaminated drinking water, other possible explanations such as genetic defects in the fetuses and cluster by chance as in the study from Bulgaria could not be ruled out
Caution and avoidance of exposure is best in pregnant mothers when a credible environmental threat is identified as more research adds to the current body of medical knowledge on this subject.
This information is for educational purposes only and not a substitute for professional medical care or advice. Always follow your healthcare provider’s instructions.
Image credits: Pfizerpro.com and A.D.A.M. October 2012
Is it conceivable to believe that an individual can be too clean for their own good? Maybe.
We know that the immune system in all mammals- a group that includes humans too, has an adaptive capability that matures and becomes more savvy as the challenges mounted by invading germs are responded to over a lifetime. Basically, “the troops remain battle ready when they are continually fighting and winning”. This has been cast as a potential mutually beneficial relationship for the body and the invading germs in a theory proposed to explain the rising trend of allergy and immune system mediated diseases called the ‘hygiene hypothesis’. This theory maintains that living in very clean and hygienic environments robs one of the exposure to microbial organisms which are beneficial for the maturation and ability to distinguish invaders from what belongs to the body. An abnormal maturation process involving the immune system’s cells and antibodies may then arise and predispose individuals to varying levels of abnormal immune responses which manifest in various disease forms.
Needless to say, this is still a theory and not validated as a scientific fact yet. Researchers from the University of Michigan School of Public Health observed a pattern corroborating another aspect of this theory, more amenable to scientific scrutiny. They examined data from the National Health and Nutrition Survey (NHANES) for the period 2003-2006. Two common environmental toxins, Triclosan and Bisphenol A both of which have known effects on the delicate balance of the immune and hormonal systems respectively in the body were looked for in patients aged 6 and older who also had diseases attributable to immune dysfunction for example, Hay fever. Their findings published online in November 2010, showed a relationship between having high levels of this Triclosan in the body and immune dysfunction associated disease. Triclosan, is an antimicrobial agent and is ubiquitous in the home environment. Diapers, antibacterial soaps, and toothpaste are some household items that contain this product. The higher levels of Triclosan seen in these patients may have sufficiently altered the population and type of microbes that these individuals would have been normally exposed to and therefore led to abnormal maturation of their immune system over time and subsequently modified their overall immune response and foster the development of allergy related disease states. This writer has observed trends not subjected to scientific testing at any level yet, in children of first generation West African immigrants born in the USA (Bronx NY) who go on to develop varying levels of allergy symptoms which are mediated at many levels by immune dysregulation. The parents of these patients demonstrate no such problems and a cautious assumption may be to say their earlier childhood exposures in the developing world to different microbial agents in childhood may have fostered a proper maturation and development of their immune systems, i.e the troops (immune cells) remained battle ready and matured as anticipated. This perhaps fostered the innate ability of the immune system to distinguish self from non-self and keep the focus on the invading germs.
As we push the frontiers of medicine daily in the 21st century, some of these basic questions remain unanswered and beg for more research and elucidation of the facts. Until then, we will keep the hygiene hypothesis in the realm of hypotheses and continue to take all necessary precautions for clean, safe healthy skies, water, air, soil, food and above all planet. Louis Armstrong’s timeless classic, still chimes, “what a wonderful world”.
The information here is for patient health education purposes only and is not intended to serve as or replace the advice of a physician, please consult your healthcare provider as appropriate.
A family I took care of recently at the hospital, wondered why I suddenly had so many questions to ask about their pet Iguana "Izzy". Far from having an axe to grind with just Iguanas or anger directed at "Izzy", we've know for sometime that all members of the reptile and amphibian family that have become domesticated and favorites for family pets can be fun for the family, but they can just as easily harbor a bacteria that could make young children very sick. Turtles, frogs, snakes, geckos, horned toads, salamanders, and chameleons are other common examples of this family of animals.
The control of salmonella and similar germs transmitted from contaminated water and food remain one of the great triumphs of public health measures. Most people some of whom own these pets actually still think of only water and food-borne sources of transmission as being possible for salmonella as a result. This is incorrect since amphibian and reptilian pets still leave the door open for salmonella to cross from these animals to unsuspecting humans, their contacts and potentially cause very serious problems in children and adults. Reptiles and amphibians very frequently harbor these germs.
The CDC cautions families with children aged less than 5-years to especially avoid these families of animals for pets. Smaller sized pet Turtles were banned for sale in 1975 in the USA because little children were more likely to put the small animals in their mouth and increase likelihood of transmission through the gut. Children in this age group have developing immune systems and this makes them especially vulnerable to serious complications from salmonella infection though the same risk is applicable to all ages. These animals despite being kept clean and appearing healthy can transmit these bacteria during handling, cage cleaning etc.
Find useful tips below from the CDC on precautions if your family has a reptilian or amphibian animal as a pet to reduce salmonella transmission from the animals to their human owners. Remember, “an ounce of prevention is worth a pound of cure”.
How do I reduce the risk of Salmonella infection from reptiles and amphibians?
- Wash your hands thoroughly with soap and warm water immediately after touching a reptile or amphibian, or anything in the area where they live and roam. Use hand sanitizer if soap and water are not readily available.
- Adults should always supervise hand washing for young children.
- Do not let children younger than 5 years of age handle or touch reptiles or amphibians, or anything in the area where they live and roam, including water from containers or aquariums.
- Keep reptiles and amphibians out of homes with children younger than 5 years old or people with weakened immune systems.
- Reptiles and amphibians should not be kept in child care centers, nursery schools, or other facilities with children younger than 5 years old.
- Do not touch your mouth after handling reptiles or amphibians and do not eat or drink around these animals.
- Do not let reptiles or amphibians roam freely throughout the house or in areas where food or drink is prepared, served, or stored, such as kitchens, pantries, or outdoor patios.
- Habitats and their contents should be carefully cleaned outside of the home. Use disposable gloves when cleaning and do not dispose of water in sinks used for food preparation or for obtaining drinking water.
- Do not bathe animals or their habitats in your kitchen sink. If bathtubs are used for these purposes, they should be thoroughly cleaned afterward. Use bleach to disinfect a tub or other place where reptile or amphibian habitats are cleaned.
- Wash any clothing the reptile or amphibian might have touched.
- Use soap or a disinfectant to thoroughly clean any surfaces that have been in contact with reptiles or amphibians.
- Dr. Diji Vaughan