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Eye color and hypertension
G D Friedman1, J V Selby, C P Quesenberry
1Division of Research, Kaiser Permanente Medical Care Program, Oakland, California 94611.
Insights
Individuals with brown eyes have a higher risk of developing essential hypertension compared to those with lighter eye colors. This finding suggests a potential link between eye color and hypertension etiology.
Area of Science:
- Epidemiology
- Genetics
- Public Health
Background:
- Essential hypertension is a significant global health concern.
- Identifying novel predictors of hypertension is crucial for preventative strategies.
Purpose of the Study:
- To investigate potential predictors of essential hypertension.
- To explore the association between eye color and hypertension development.
Main Methods:
- A case-control study involving 1,031 individuals progressing from normotension to hypertension and 1,031 matched controls.
- Blood pressure status was documented through multiphasic screenings and clinical records.
- Statistical analyses controlled for various confounding factors including race, sex, BMI, and family history.
Main Results:
- Individuals with brown eyes demonstrated a 1.5-fold increased risk of developing hypertension compared to those with non-brown eyes.
- This association remained significant after adjusting for multiple potential confounders.
- Partial confirmation was observed in three independent study groups, including dizygotic twins and large-scale screening data.
Conclusions:
- A weak but consistent association exists between brown eye color and an increased risk of essential hypertension.
- While not suitable for clinical screening, this finding may offer insights into hypertension etiology.
- Further research is warranted to explore the underlying biological mechanisms, potentially involving melanin and catecholamine metabolism.
Abstract:
We searched for predictors of essential hypertension in 1,031 persons aged 30-49 who were observed to progress from normotension to hypertension, as compared to an equal number of matched subjects who remained normotensive. Blood pressure status was well documented in both multiphasic screenings and clinical records. Compared to persons with each lighter eye color, those with brown eyes were more prone to develop hypertension, with relative risk of 1.5 (95% confidence interval 1.18-1.96) compared to all persons with nonbrown eyes. The association persisted after control for race, sex, body mass index, alcohol use, educational level, parental history of hypertension, and among whites, for ethnic origin as crudely estimated by last name. Partial confirmation was obtained in three largely independent study groups: 1) 25 pairs of eye-color-discordant dizygotic twins; 2) 894 pairs of incident hypertensives and controls selected only with multiphasic screening blood pressure measurements; and 3) cross-sectional analysis of 152,018 multiphasic screenees. The weak association of eye color with hypertension clearly requires further confirmation. Although it has little potential for use in screening or clinical care, it may have implications regarding etiology. Areas for further exploration include the close metabolic relation of melanins to catecholamines, both derived from the amino acid tyrosine, and the possibility that dark-eyed persons react more quickly and strongly to stimuli than light-eyed persons.