Epidemiological Studies on Environmental Stressors from Tobacco to Pesticides

W. Susan Cheng, PhD, MPH

Rebecca Carlstrom, MPH

Sukaina Hussain, MPH

Healthy Lawn Symposium

Oct 31, 2014

Two Presentations

Allergies, Asthma, and Environmental Stressors

By Dr. Susan Cheng, PhD, MPH

Tobacco-Free Campus Research Study and Initiative

By Rebecca Carlstrom, MPH & Sukaina Hussain, MPH

Effects of Pesticides on Health (especially Asthma)

W. Susan Cheng, PhD, MPH

Master of Public Health Department

Effects of Pesticides on Health

Pesticide exposure has been shown to be correlated to:

Cancer (leukemia, non-Hodgkin’s lymphoma)

Birth defects (cleft palate, limb reduction)

Endocrine disruption (fertility issues, endometriosis)

Neurological disorders (dizzy, lightheaded, confused)

Weakened immune system/response

Asthma (can trigger, initiate, or exacerbate)

Asthma

Asthma is “an inflammatory disease of the lung . . . Once considered a minor ailment affecting only a small portion of the population, asthma is now the most common chronic disorder of childhood.”

Sources: National Heart Lung and Blood Institute, National Institutes of Health

Asthma

Environmental and genetic links

Familial link or atopy

Inherited tendency for allergies

Triggered by “allergens”

Exposure in early childhood:

Viral infection or allergen

Once triggered, inflammation occurs in airways, compromising breathing

Sources: National Heart Lung and Blood Institute, National Institutes of Health

Signs and Symptoms of Asthma

Recurring periods of wheezing

Chest tightness

Shortness of breath

Coughing

Sources: National Heart Lung and Blood Institute, National Institutes of Health

Treatment of Asthma

Avoiding environmental triggers

Asthma Action Plan

Medications (preventive)

Inhaled Corticosteroids

Antihistamines

Rescue medications

Albuterol

Steroids

Sources: National Heart Lung and Blood Institute, National Institutes of Health

Epidemiology of Asthma

25 million people with known asthma in the US (1 in 12)

½ have asthma attacks every year

$58 Billion approximate annual costs

Medical care, lost school and work days, early deaths

9 people die daily from asthma attacks

Epidemiology of Asthma

6.2 million children under 18 years old have asthma

More prevalent among boys than girls among children

Among adults, more women than men have asthma

Majority of patients with asthma have allergies

Children can “outgrow” allergies after 6 years old

Increased risk for lifelong asthma with allergies, eczema, or parents/familial link with asthma

Epidemiology of Asthma

Asthma is increasing in incidence:

From 2001 – 2009, # diagnosed increased by 4.3 million ppl

African-American children increased by 50%

Roughly 1 in 9 African Americans, and 1 in 6 AA children have asthma

Estimated 50 million Americans have allergies

Over half of asthmatics have allergies too

Environmental Triggers for Asthma

Occupational asthma

triggered by chemical irritants or industrial dust

Environmental asthma

tobacco smoke

air pollution

chemicals or dust in the workplace

compounds in home products

aerosol sprays (e.g. hair sprays)

Tobacco Smoke and Asthma

International Study of Asthma and Allergies in Childhood (ISAAC) surveyed 3000 adolescents aged 13-14 yo

Smokers twice as likely to have asthma or rhinitis

Boys more likely than girls

M Gomez, et al. Adolescent smokers are at greater risk for current asthma and rhinitis. Int J Tuberc Lung Dis. 13 (8): 1023-1028, 2009.

Pesticides and Asthma

Pesticides can trigger asthma attacks, especially in children

More susceptible (children breath in more air than adults, relatively)

More direct contact with lawns and shrubs/greens

More repeated (chronic) contact with pesticides in yards

Source: A Glaser. Asthma, Children and Pesticides. National Coalition Against the Misuse of Pesticides. Vol 25, No 2, 2005.

Pesticides and Asthma

Pesticides can trigger hypersensitivity in airways, making them more susceptible to an asthma attack at subsequent exposure to pesticides

Johns Hopkins researchers hypothesize that “pesticides alter the nerve function controlling the smooth muscle lining of the airway, causing the airway to contract and restrain airflow” and thus an asthmatic attack

27 of the 30 most common lawn pesticides are irritants or stimulate hypersensitivity in the airways; may trigger or exacerbate asthma in children

Source: A Glaser. Asthma, Children and Pesticides. National Coalition Against the Misuse of Pesticides. Vol 25, No 2, 2005.

Pesticides and Asthma Studies

In 2003, a study of 3,000 Lebanese children reported correlation between home and garden pesticide exposure, proximity to a treated agricultural field, or occupation use by a family member with asthma

In 2004, a study of 4,000+ school aged children in CA found that exposure to herbicides in the 1st year of life increases risk 4.5 times of developing asthma by age 5

Toddlers and young infants are at much greater risk

MT Salem, et al. Early life environmental risk factors for asthma: findings from the children’s healthy study. Environ Health Perspect 2003; 112: 760-765. JD Thrasher, et al. Immunologic abnormalities in humans exposed to chlorpyrifos: preliminary observations. Arch Environ Med 1993; 48:89-93.

Pesticides and Asthma Studies

In Spain, a study of 405 children ages newborn to 14 years old reported on a subset of 275 children at age 4 and reported that evidence of pesticides in the blood was associated with wheezing

Looked specifically at DDT and HCB persistent organic pollutants

Although these substances were banned in the 70’s, many still evident in soil samples and bioaccumulate in children who have increased contact

M Gascon et al. Persistent organic pollutants and children’s respiratory health: The role of cytokines and inflammatory biomarkers. Environment International. 2014; 69: 133-140.

Pesticides and Asthma Studies

Cord blood study of 2,050 infants found levels of pesticides in blood associated with allergies & eczema; children with higher levels of pesticides in their blood are at increased risk of asthma (strong, positive association)

In Mexico, cord blood from 613 infants were analyzed for presence of pesticides and IgE levels (marker for allergic response); pesticides were associated with higher IgE levels in the infants.

Exposure to insecticides, herbicides, and fungicides have all been shown to be correlated with higher rates of asthma

W. Karmaus, et al. Infections an datopic disorders in childhood and organochlorine exposure. Arch Environ Health 2001; 56:485-492. E Hernandez et al. Prenatal determinants of cord blood total immunoglobulin E levels in Mexican newborns.

Some Good News

Microbiome diversity may decrease risk of asthma and allergies in children

Two studies follow:

Diversity of microbiome

Early exposure to bacteria

Dust in Homes with Dogs May Protect Against Allergies, Asthma

Previous study: infants in homes with dogs have lower risk of developing childhood allergies

Dog-associated house dust decreases allergic inflammation (asthma)

Dust collect wide diversity of bacteria from dogs

Toddlers are exposed to a wider variety of bacteria from this household dust from the dogs

Increases the biodiversity of the toddlers’ microbiome

Lactobacillus johnsonii could potentially prevent airway inflammation (asthma) from exposure to allergens or RSV infection

KE Fujimura et al. House dust exposure mediates gut microbiome Lactobacillus enrichment and airway immune defense against allergens and virus infection. Proceedings of the National Academy of Sciences DOI: 10.1073/pmas.1310750111 (2013).

Early Exposure of Bacteria

Birth cohort enrolled since 2005 with 560 children enrolled from four cities

Baltimore, Boston, New York, and St. Louis

All children have parental history of asthma

Examined exposure to cat, dog, roaches, dust mites, & mice

Findings: cats, mice, and roach exposure in early life decreased risk of wheezing later in life

Substudies: compare 104 children who (a) no asthma or allergies; (b) wheezing only; (c) allergies only; (d) both wheezing and allergies

Findings: those exposed to dust with bacteria in it were most likely to be in the no asthma or allergies group

High bacterial diversity and early exposure to bacteria are both protective against allergies and asthma

SV Lynch et al. Effects of early life exposure to allergens and bacteria on recurrent wheeze and stopy in urban children. Journal of Allergy and Clinical Immunology.

Questions?

References List National Heart Lung and Blood Institute, National Institutes of Health

National Health Interview Survey, National Center for Health Statistics, Centers for Disease Control and Prevention

National Center for Health Statistics

M Gomez, et al. Adolescent smokers are at greater risk for current asthma and rhinitis. Int J Tuberc Lung Dis. 13 (8):

1023-1028, 2009.

A Glaser. Asthma, Children and Pesticides. National Coalition Against the Misuse of Pesticides. Vol 25, No 2, 2005.

MT Salem, et al. Early life environmental risk factors for asthma: findings from the children’s healthy study. Environ Health Perspect 2003; 112: 760-765.

JD Thrasher, et al. Immunologic abnormalities in humans exposed to chlorpyrifos: preliminary observations. Arch Environ Med 1993; 48:89-93.

M Gascon et al. Persistent organic pollutants and children’s respiratory health: The role of cytokines and inflammatory biomarkers. Environment International. 2014; 69: 133-140

W. Karmaus, et al. Infections an datopic disorders in childhood and organochlorine exposure. Arch Environ Health 2001; 56:485-492.

E Hernandez et al. Prenatal determinants of cord blood total immunoglobulin E levels in Mexican newborns.

KE Fujimura et al. House dust exposure mediates gut microbiome Lactobacillus enrichment and airway immune defense against allergens and virus infection. Proceedings of the National Academy of Sciences DOI: 10.1073/pmas.1310750111 (2013).

SV Lynch et al. Effects of early life exposure to allergens and bacteria on recurrent wheeze and stopy in urban children. Journal of Allergy and Clinical Immunology.