Childhood Depression and Adult Obesity

Childhood Depression – Link to Adult Obesity?

Epidemiology

65% of Americans are considered overweight and 18% are considered obese with a body mass index (BMI) > 30 kg m2 (Flegal 2002)
10% of Americans are thought to suffer from major depression (MDD) (Kessler 1994)
2% of Children and 4-8% of adolescents suffer from MDD (Birmaher 1998)

Adverse Health Effects of Obesity (Must 1999)

Type II Diabetes Mellitus
Gallbladder disease
Coronary heart disease
High Blood Cholesterol
Hypertension (HTN)
Osteoarthritis
Obese females on average earn lower wages
Obese males are less likely to marry
Thought that obesity leads to depression because the social stigmatization causes embarrassment, shame, and guilt
Most studies have focused on obesity causing depression and not the reverse (Stunkard 2003)

Neurobiological Link for Depression causing Obesity (Wurtman 1993)

Serotonin connection – theorized that low serotonin levels in depressed patients cause them to ingest meals high in carbohydrates
Carbohydrates derive their behavioral effects by increasing blood insulin. Insulin in turn depresses the production of most large neutral amino acids except tryptophan. Increased tryptophan causes increased serotonin in the brain and decreased depression

Serotonin Connection

Overweight individuals report eating more when anxious, depressed, or alone. Normal weight individuals do not show these behaviors.
Plasma serotonin levels have been shown to be lower in obese carbohydrate cravers than obese/lean non-carbohydrate cravers. Consumption of large carbohydrate meals in obese individuals is often associated with mood disturbances. (Wurtman 1993)

Review of Recent Literature

Study #1

Pine et al (2001) studied children 6 to 17 yrs old with major depression (n=90) or no psychiatric disorder (n=87)
Children were followed up 10 to 15 yrs later
Psychiatric status was evaluated at both intake and follow-up
BMI was recorded in adulthood
Participants with major depression had a BMI of 26.1+/- 5.2 as adults while those without depression had a BMI of 24.2 +/- 4.1
First study to show a correlation between Childhood Depression and Adult BMI
A number of other confounding variables were examined such as age, gender, cigarette and alcohol use, and poverty
The only other variable that correlated with obesity was poverty
Using multivariate statistics it was shown that depression correlated with an increased BMI independent of poverty
Limitation – small study size

Study #2

Goodman et al (2002)
A prospective cohort study of 9374 adolescents in grades 7 to 12 who completed in home interviews for the National Longitudinal Study of Adolescent Health
Depressed mood was assessed with the Center for Epidemiologic Depression Scale
BMI was calculated from self-reported height and weight.
Obesity was defined as BMI> 95th percentile, overweight as BMI >85th, but less than 95th. Normal as < 85th percentile.
Assessments were made at baseline and after 1 year of follow-up.
At baseline 12.9% were overweight, 9.7% were obese, and 8.8% had depressed mood.
Baseline depression was not correlated with baseline obesity.
Among the 9.7% who were obese at follow-up, 79.6% were obese at baseline, 18.6% were overweight, and 1.8% were normal weight at baseline.
Having depressed mood at baseline independently predicted obesity at follow-up among those not obese at baseline (odds ratio 2.05; 95% confidence interval 1.04, 4.06).
Baseline obesity did not predict follow-up depression.
Similar to previous study multiple confounding variables were controlled for: age, race, gender, parental obesity, # of parents at home, and socioeconomic status.
Conclusion – Adolescent depression leads to adolescent obesity

Study #3

Richardson (2003)
Used data from a longitudinal study of a birth cohort between April 1, 1972 and March 31, 1973, in Dunedin, New Zealand (N=1037).
The data included regular diagnostic mental health interviews and ht/wt measurements throughout childhood and adolescence.
Logistic regression analysis was performed to assess the relationship between major depression in early or late adolescence and the risk for obesity at 26 yrs of age.
Results: Major Depression occurred in 7% of cohort during early adolescence (11, 13, and 15 yrs of age) and and 27% during late adolescence (18 and 21 yrs of age). At 26 yrs of age, 12% were obese.
After statistical analysis – depressed late adolescence girls were at greater than two fold increased risk for obesity in adulthood compared to non-obese female peers (RR 2.32, 95% confidence interval 1.29-3.83).
A dose-response relationship between the number of episodes of depression and risk for adult obesity was also found in late adolescent girls.
Difference between previous studies in gender – depressed adolescent boys show no increase in adult obesity. Also, depression in early adolescent females does not led to an increase in adult obesity.
Results of this study may be attributable to classifying adolescents into different age groups. Also, a specific Depression Scale was not used.

Summary

The results of the three studies indicate that depression in childhood and adolescence may lead to adolescence or adult obesity
Both obesity and depression are increasing worldwide for reasons that are unknown
Obesity is thought to be a biologically heterogeneous disorder
It is possible that for a subgroup of obese patients that depression is an important risk factor
These patients may eat large meals to counteract low serotonin levels. SSRI’s (selective serotonin reuptake inhibitors) may be important in these patients not only to improve their depressive symptoms, but also to maintain their weight … more studies are needed.
In addition to depression, other social factors need to be addressed that could lead to depression – declining levels of physical activity, increasing social isolation, and increasing socioeconomic inequality.