Cathy Vakil is a family doctor in Kingston, Ontario, and an assistant professor in the Department of Family Medicine at Queen's University. She is an active member of the Canadian Association of Physicians for the Environment (CAPE) board of directors and the Ontario College of Family Physicians Environmental Health Committee. She co-authored the Pesticide Literature Review published by the Ontario College of Family Physicians in 2004. As a follow-up to her earlier posting in this series, Docs Talk asked Dr. Vakil to reflect on recent developments in pesticide science and policy.
Docs Talk: What prompted you to become involved in pesticide issues?
Dr. Vakil: As a family doctor, I consider preventative medicine the best way to deal with health issues. Maintaining a healthy environment is key to a healthy population. There has been a lot of controversy about the health effects of pesticides for many decades, particularly with respect to cancer, and especially childhood cancer. I became more aware and concerned about pesticides when my children were young and I was worried about the harmful effects of contaminants on the food they were eating. This led me to explore the research on pesticides and health.
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Docs Talk: What are some ways that pesticides can affect our health?
Dr. Vakil: Pesticides can cause cancer (including lymphoma, leukemia, brain cancer and prostate cancer), developmental delays in children, respiratory problems like asthma, neurological diseases such as Parkinson's disease, birth defects, and reproductive problems in couples trying to conceive. Studies since the 1960s have indicated these links, and in the past few decades, research has consistently showed associations between pesticide exposure and these illnesses.
Docs Talk: Since the OCFP published its Pesticide Literature Review in 2004, what kind of research has been done to better understand the health impacts associated with pesticides?
Dr. Vakil: There have been a number of high-quality studies on pesticides and health since 2004. A very recent study (Vinson, 2011) pooled results of 40 studies in a meta-analysis (where results of a number of studies are combined to increase numbers and strengthen the results). It found that the risk of a child developing lymphoma or leukemia increased significantly when the mother was exposed to pesticides during pregnancy. The risk of brain cancer was correlated with the father's exposure before and after birth. Importantly, this exposure was due to household exposure, the type that bans on so-called cosmetic pesticides aim to eliminate. This underlines the importance of protecting pregnant women and men of child-bearing age from the harmful effects of pesticides in order to protect the fetus and young child.
Another meta-analysis (Bailey, 2010), which looked at home use of pesticides, found an increased risk of childhood leukemia with pest-control treatments during pregnancy and early childhood years. This adds to the evidence that pesticides can cause childhood leukemia.
A study of a large cohort of children in New York City examined effects of pesticides (measured in urine of the pregnant mothers) on neurodevelopment of children over a number of years (Engel, 2007, 2011). This study showed some deficits in mental development following organophosphate exposure during pregnancy on newborns, babies of 12 months and children at six to nine years old.
Docs Talk: How effective do you think municipal and provincial bans on lawn and garden pesticides are in reducing our exposure to these toxic chemicals?
Dr. Vakil: An Ontario Ministry of Environment study showed that water quality improved after the province implemented legislation to ban the use of cosmetic pesticides. Concentrations of several common herbicides and insecticides were significantly lower after the ban took effect than before 2008. In some streams, pesticide levels were as much as 97 per cent lower after the ban was enforced.
Another study done in 2004 in New York City examined birth weight and exposure to insecticides. (It is important to note that low-birth-weight babies are at higher risk for many health problems in childhood and later in life.) A ban on insecticide use was enforced in 2001 in New York City. Babies born before the ban had higher levels of pesticides (measured in the umbilical-cord blood) and lower birth weights. Babies born after the ban had substantially lower concentrations of pesticides in their umbilical cords, and no depression of fetal growth. This is strong evidence that bans on pesticides lead to measurable and documented improvements in children's health.
I am pleased that many municipalities and provinces have recognized the health problems associated with pesticides and banned the use of these chemicals on lawns and gardens. I look forward to the day that cosmetic pesticide use is eliminated in every province in Canada.
Docs Talk: What advice can you offer to people who want to reduce their exposure to pesticides?
Dr. Vakil: People who want to reduce their exposure to pesticides should not use any unnecessary pesticides of any kind in their home or garden. If you use a lawn company, hire one that uses natural and organic methods of weed and pest control. Opt for local, organic food whenever possible.
As citizens, it is also important to support municipal and provincial legislation for bans on the use of cosmetic pesticides. If you live in a province that hasn`t already banned cosmetic pesticides, phone or write to your representatives and let them know that you want legislation to ensure a clean environment for you and your children. Now, people in B.C. have the opportunity to share their views with lawmakers who are considering a ban. Show your support for a ban on lawn and garden pesticides in British Columbia.
- Vinson F et al. "Exposure to pesticides and risk of childhood cancer: a meta-analysis of recent epidemiological studies." Occup Environ Med. 68(9):694-702. 2011 Sep; Epub 2011 May 23.
- Bailey HD et al. "Exposure to professional pest control treatments and the risk of childhood acute lymphoblastic leukemia." Int J Cancer 129(7):1678-88. 2011 Oct 1; Epub 2011 Feb 11.
- Engel SM et al. "Prenatal organophosphate metabolite and organochlorine levels and performance on the brazelton neonatal behavioral assessment scale in a multiethnic pregnancy cohort." Am J Epidemiol 165(12):1397-1404. 2007..
- Engel SM et al. "Prenatal exposure to organophosphates, paraoxonase 1, and cognitive development in childhood." Environ Health Perspect 119:1182-1188. 2011.
- Whyatt R. et al. "Prenatal Insecticide Exposure and Birth Weight and Length among an Urban Minority Cohort" Environ Health Perspect 112(10): 1125-1132. July 2004.