TV and Hypertension

Research conducted by: Perrie E. Pardee, Gregory J. Norman, Robert H. Lustig, Daniel Preud’homme, and Jeffrey B. Schwimmer

Case study prepared by: Robert F. Houser and Andrew Kennedy

Overview
A strong, evidence-based association exists between TV viewing time and the risk of being obese in children and adolescents.  Little or no research, however, has explored adverse health outcomes associated with TV viewing among obese children.  This study aimed at identifying whether or not time spent watching TV is associated with hypertension (high blood pressure) in obese children.

Obese children aged 4 to 17 years were recruited and evaluated at three pediatric centers.  Obesity was defined as a body mass index (BMI) greater than or equal to the 95th percentile for the child’s age and gender.

Questions to Answer
Is TV watching associated with hypertension in obese children?

Design Issues
The study involved a cross-sectional design, which prevented the determination of possible causality among the associations found.  There could be unmeasured factors that play a role in the association between TV viewing and hypertension.


Descriptions of Variables
Variable Description
Hypertension

Defined as a systolic and/or diastolic blood pressure greater than or equal to the 95th percentile for the child’s age, gender, and height
Age

A child’s age in years
BMI A child's body mass index, calculated as:
(weight in kilograms) / (height in meters)2
Hours of TV/day

An estimate of a child’s average daily time spent watching TV in hours


References

Pardee, P. E., Norman, G. J., Lustig, R. H., Preud’homme, D., Schwimmer, J. B. (2007). Television viewing and hypertension in obese children. American Journal of Preventive Medicine, 33, 439-443.

Luma, G. B., Spiotta, R. T. (2006). Hypertension in children and adolescents. American Family Physician, 73, 1558-1568.

 

Links

Pardee et al. article
Luma et al. article


Exercises

Please read the Pardee et al. article before proceeding with the exercises.  To perform t tests, please refer to Table 1 for the means, standard deviations, and sample sizes of the variables.

  1. Conduct an independent samples t test comparing the mean BMI of subjects without hypertension to the mean BMI of subjects with hypertension.  What do you conclude?
  2. Conduct an independent samples t test comparing mean hours spent watching TV per day between subjects without hypertension and subjects with hypertension.  What do you conclude?
  3. Conduct an independent samples t test comparing the mean age of subjects without hypertension to the mean age of subjects with hypertension.  Is there a significant difference?
  4. Could age have been a confounder in the association between TV watching and hypertension?  Why or why not?
  5. What could be the possible mechanism(s) behind the results of this study?  In other words, what might be the driving factor(s) behind the association between TV watching and hypertension in obese children?
  6. Do you think the authors’ recommendations are broad enough?  What might you recommend?