Economic disadvantage modifies the association of height with low mood in the US, 2004: the disappointment paradox.

INTRODUCTION

Taller stature is associated with greater health potential reflected by reduced risks for coronary heart disease (CHD) and depression. Previous studies demonstrated that the reduced CHD and depression risks associated with tall stature were eliminated by financial disadvantage in adult life.

HYPOTHESIS

The reduced risk of depression, defined as low mood, associated with taller stature is eliminated by adult financial adversity. This study also attempts to replicate earlier findings, that the reduced risk of CHD associated with taller stature is eliminated by adult financial adversity.

METHODS

The Behavioral Risk Factor Surveillance System is an ongoing survey of the adult population of the US conducted by state health departments and the Centers for Disease Control and Prevention, providing a representative sample of 45,210 adults resident in USA in 2004 with data on low mood and CHD. Low mood was defined by self-reported low mood for more than 15 days in the previous month and CHD by a diagnosis of angina or coronary heart disease. Short stature was defined as the lower 20% of sex-standardised heights and economic disadvantage as household income below $15,000 per annum.

RESULTS

Tall stature was associated with a statistically significant reduced risk for low mood in the entire population. After stratification by economic disadvantage, taller individuals in the higher income stratum maintained a statistically significant reduced risk of low mood, with an odds ratio (and 95% confidence interval) of 0.90 (0.90, 0.91) after adjustment for potential confounding factors and application of the survey weighting. In contrast, taller stature represented a raised risk for low mood in the lower income stratum, with a statistically significant odds ratio of 1.27 (1.26, 1.28) with weighting. This effect modification was confirmed by interaction testing, producing an odds ratio for interaction of 1.39 (1.37, 1.39; p<0.001). This phenomenon was most profound among white males, with an odds ratio for interaction of 2.20 (2.16, 2.25). Effect modification by economic disadvantage was also observed for the association of height with CHD, producing an odds ratio for interaction of 1.57 (1.56, 1.59; p<0.001).

CONCLUSIONS

Although taller stature indicates better heath potential in terms of low mood and CHD, this potential is eliminated by economic disadvantage in later life. Indeed, taller stature is associated with an increased risk among those who experience economic disadvantage. Possible explanations are that childhood adversity reducing height may confer resilience against some forms of adult adversity. Alternatively, as taller stature signals greater childhood advantage, then financial adversity may represent a form of disappointment among this group: the disappointment paradox.