Does stress during childhood affect children's current and future physical health?
I remember having a lightbulb moment my first summer after finishing high school. I was working in my rural South Dakota hometown as a nurse aide in our hospital, trying to get as much experience in the medical field as possible before starting college as a pre-med student. Since it was a small community hospital, I got see a wide range of medical problems and patients -- from babies to the elderly. I saw everything from heart attacks to pneumonia to broken bones and motorcycle accidents. But what really made me stop in my tracks was a little girl who was back in the hospital for the second time in only a few weeks.
She was pretty small for her age, and though I can't remember exactly what illness she had, we all found it quite unusual that she was having such a hard time staying healthy. And we were also surprised about how HARD she was hit by her illness...so hard she had to stay in the hospital for a few days each time. Although I didn't know her family personally, it became fairly obvious over the course of their stay that her family was struggling financially, which was unfortunately not uncommon in the area. In my hometown, the 2000 census put the child poverty estimate in our town at over 30%, which is beyond tragic. We all suspected this little girl was dealing with a LOT of stress, which made me wonder whether the stress she was dealing with was related to her physical health.
It is usually pretty surprising when kids don't bounce back after a bout of illness, so this girl's case was especially puzzling to me. I asked myself, Why is this little girl struggling to recover from her illness? And why did it hit her so hard? Could her difficulty with staying healthy have anything to do with the environment she is living in?
That's when I knew I NEEDED to study psychology on my path to becoming a doctor. I HAD to find out what was making this little girl so sick time and time again. Little did I know that psychologists and doctors had realized this association years earlier and that it was suddenly becoming a hot topic in research, parenting, and policy circles.
So here's the short answer to my question of whether childhood stress affects current and future health:
YES. ABSOLUTELY YES, IT DOES.
The slightly longer version: Yes! But stress doesn't affect everyone the same. Some people can get hit especially hard by something stressful -- such as the death of a parent or growing up in an abusive household -- but others seem to recover pretty well. Some may have troubles with physical health problems, others with mental health. There are those who have both physical and mental health problems following stress, and there are some people who have none! I love to learn about what protects people from stress (luckily there are a lot of things) but I'm going to save those for future posts. For now, let's talk a little about some of the general effects of stress on physical health.
How poverty affects children's health
Children living in poverty are more likely to suffer from health problems during childhood. Having fewer financial resources in childhood and adolescence is related to poorer overall health. This research supports my earlier idea that the little girl in the hospital might suffer additional health problems from living in poverty. Children in poorer and more dangerous neighborhoods are also more likely to become overweight than children from safer neighborhoods, which can lead to obesity-related problems years down the road.
Childhood poverty is a strong predictor of death in infancy. Poorer countries have higher infant mortality rates than richer countries. Even within countries, infants from poor families are much more likely to die than those from well-off families. Infants from poor families who do survive are more likely to be born underweight, which is related to greater health problems during their early years as well as greater likelihood of developing heart disease as adults. These health issues are often due to the baby's experiences and exposures during pregnancy, including a lack of prenatal care, which start infants off at a disadvantage (more on that in a future post!).
How stressful events affect children's health
Other stressful events besides poverty are also bad for children's health, with more stressful experiences associated with greater health problems. Children who experienced maltreatment or family violence who had symptoms of trauma exposure, are around 4 times more likely to have asthma or digestive problems. The more traumatic experiences and stress children are exposed to, the more health problems they are likely to have. Below are some of the experiences I'm referring to when I say "stressful experiences" or "adversity":
These are some of the experiences that are often referred to as "adversity" or "stressful life events." This is, of course, not an exhaustive list!
One of the most interesting things about early stress and poverty is that it doesn't just affect a child's current health. It can affect their health as adults, too. So the problems we see for children experiencing stress aren't likely to disappear fully even if their stress is reduced during childhood.
How childhood poverty affects adult health
Growing up in poverty has been associated time and time again with higher risk for early death and for a number of health problems, including heart disease, stroke, diabetes, respiratory disease, obesity, and even cancer. The more years a person lives in poverty, the higher risk they have for these health problems as adults.
Here's a hypothetical graph showing the direction of the association between years in poverty and physical health problems. There are no numbers on the graph to make it clear that this isn't using data directly from a study -- just showing a pattern.
You might be wondering, "Are we sure that childhood stress is that important? Couldn't it be that poor children grow up to be poor adults who can't afford good health care?" That is certainly part of story, since children in poverty are more likely to grow up to be poor adults. However, there are also many studies showing that even poor children who grow up to be financially stable as adults have more health problems than their peers who have always been financially stable.
One interesting study followed a group of medical students from Johns Hopkins (a top-ranked medical school) through adulthood. Even though they were financially stable doctors in mid-adulthood, those who grew up in families with parents who had blue collar or manual labor jobs were over twice as likely (2.4 times!) to have heart disease at age 50 than the doctors who grew up with parents who had white collar jobs.
Adults who grew up in less financially secure homes are also more likely to develop a cold as an adult after being exposed to the cold virus, regardless of their financial stability in adulthood. So your childhood environment is related to your body's ability to fight off infections years down the road! Seriously?! I was so shocked when I first read this study; it was actually one of the studies that inspired me to go to grad school!
Why is childhood poverty so bad for health? Well, there are a lot of reasons! These reasons range from poverty changing how people behave, what kinds of medical care and tools for a healthy life you can afford, what kinds of opportunities you will have in the future, and how your brain and the systems in your body react to stress on a daily basis! Here's a graphic of some of these effects to give you a better idea of the scope of these effects.
Here are just some of the reasons that poverty is bad for your health!
How stressful life events in childhood affect adult health
One of the most intriguing early studies of the effects of childhood adversity on adult health showed that the more traumatic experiences a person reported, the higher their risk of physical health problems. If someone reported 4 or more out of 7 categories of childhood stress (including physical, sexual, or psychological abuse; living with someone who was mentally ill, suicidal or a substance abuser; any form of violence against their mother; ever being imprisoned) they were between 1.4 and 12 times (!) as likely to develop the following problems as someone with no traumatic experiences: alcohol or drug abuse, smoking, depression, suicide attempt, risky sex, sexually transmitted diseases, physical inactivity and severe obesity. Even scarier, the more experiences adults reported, the greater likelihood they developed heart disease, cancer, liver disease, chronic lung disease, or had skeletal fractures. Since this study, hundreds more investigations have tried to pin down the exact effects of early stress, how stress affects health, and ways to protect ourselves from negative effects of early stress. For example, my work suggests that teenagers who are closer to their mothers have a lower heart disease risk in adulthood than teenagers who were not close to their mother, so this social relationship may have a protective effect on health.
Again -- not real data here. Just showing the direction of the association between adverse childhood experiences and health problems!
This is why you may be asked by your doctor about whether there are stressful things happening in your life, such as feeling unsafe at home. Your pediatrician may ask whether your child has experienced any of the adversities mentioned above since the medical field is now more aware of "toxic stress" (really severe stress like maltreatment, violence, and parental mental illness) and it's effects on children's health. Since we know that these severe, often uncontrollable stressors are related to poorer health, it's REALLY important for your doctor (or your child's doctor) to know!
So how do stressful events "get under our skin" to negatively affect our health years down the road? A lot of the ways are similar to those mentioned above for how poverty affects health. I'll spend some time going through some of these pathways in the next few weeks, so stay tuned. These pathways are a major focus of my research, and I love "nerding out" about them because I find them fascinating!
Why is it helpful to know about the impact of stress on health?
This is such an important question for all of us to think about, and we'll likely all have different answers. Here are some of the ways I've found that knowing stress affects health can help you:
Knowing that stress during childhood negatively impacts health helps us to understand that humans are COMPLICATED. While we might cast blame on an individual for their choices or their circumstances, it's important to remember that past experiences can really shape who we become and make people more likely to make choices that may not be good for them in the long run. However, we're not ONLY a product of our pasts -- we certainly do have some control over our choices and our futures! But it is SO important to remember that people have both positive and negative experiences that have shaped them into who they are today.
Knowing how much our childhood environment affects us can give us a lot of insight into our own lives. You might wonder why you think or behave a certain way, why you have particular strengths and weaknesses, and why it can be so hard to change thoughts and behaviors you've had for a long time. Understanding that your childhood experiences impacted the way that your brain developed and the way you interact with your environment can give you a better perspective! We can always work to change our life circumstances for the better, but it's healthy to remember what past experiences may have shaped us.
Understanding the HUGE impact of childhood experiences on later health can inform our decisions about how to best help children now. This can range from topics like early childhood education, to programs that reduce poverty, improvements in the child welfare and foster care systems, and health care for children. We'll talk about all of these at some point down the road, but it's good to have some background knowledge on the science of child development first.
Thanks for tuning in for my brief intro on the effects of childhood poverty and stress on physical health! Please leave any comments or questions below. I'd love to make this an interactive place!
-Jena
Coming up soon: Effects of childhood poverty and stress on mental health; how current stress affects the immune system; how our bodies respond to something stressful (and how our past experiences can change how we respond to future stressful experiences!)...