Measuring hypertension in rural children

Researchers collating data from rural areas of Haryana, Manipur, Goa and Gujarat report that 14 per cent of the children they tested had high systolic pressure, 15 per cent had high diastolic pressure and 6 per cent had both high systolic and diastolic pressure.

Interestingly, they found that blood pressure in children from the north-east Indian state Manipur was higher than in children from the other states. Blood pressure was high in all children during winter. Readings were lower in children from Goa and Gujarat than in those from Haryana.

India is fast becoming an epicentre of high blood pressure and heart disease. Cardiac ailments have now surpassed cancer to become the leading cause of death in the country.

The study, led by Rajiv Narang, reports the prevalence of primary hypertension (high blood pressure with no known cause) in the rural areas of these states. It excludes children with a history of heart or kidney disease.

Following up on their earlier work in the Ballabhgarh district of Haryana, the researchers collated systolic and diastolic blood pressures (the upper and lower readings, respectively) and demographic data for each child. They looked at socioeconomic status, height and weight (to compute the body mass index), waist circumference and the seasonal variation in blood pressure measurements.

Childhood high blood pressure is a serious public health concern in India. A preventative action plan that targets those most at risk at an earlier age would help public health administrators take proactive, age-appropriate preventive steps. This would reduce disability-adjusted life years (a measure of the number of years of life lost to ill-health and early death) and the associated health-care costs.

Children with high blood pressure are more likely to develop hypertension in adulthood, further highlighting the need for better screening. Many studies advocate regular measurement of blood pressure in children with easy-to-use, inexpensive, digital monitors. However, for such plans to work, it's essential to have an estimate of the numbers affected, the study suggests.

About 2 to 4 per cent children in the United States are hypertensive, according to American paediatric hypertension guidelines²_. The proportions are much higher in India. Stephen R. Daniels, who led the committee finalising the guidelines, says Narang and his colleagues raise a pertinent point that US standards may not be applicable to children in India. The Indian study used US guidelines for a child at the 50th percentile for height to classify the blood pressure measurements. Because taller (and older) children inherently have higher blood pressure³, the study by Narang and co-authors probably overestimates the proportion of children with high blood pressure.

Another issue that worries Daniels is that hypertension diagnosis necessitates repeat measurements over multiple visits, which wasn’t the case in the Indian study. He says, “A key issue is that they were not studying hypertension.They were studying elevated blood pressure (or prehypertension, as it was previously called),” he says. The prevalence estimates, therefore, should not be compared to other studies measuring prevalence of hypertension based on multiple visits.

However, measuring the proportion of children with elevated blood pressure could help create screening programmes and suitable public-health policies, geared at healthier diet and lifestyle choices. Daniels says study’s focus on rural areas and a large number of participants is laudable.

Joseph T. Flynn, the lead author of the US guidelines report², points to the relation between cold temperature and higher blood pressure. “This has been seen in adults as well as in children and might explain the seasonal effect,” he says. Narang and co-authors note that lower temperatures in the northern Indian states may be the reason behind the children's higher blood pressures. In coastal Goa and Gujarat, the humidity and resultant perspiration causes loss of salts, and consequently lower blood pressures, they say.

References

1. Narang, R. et al. Prevalence and determinants of hypertension in apparently healthy schoolchildren in India: A multi-center study. Eur. J. Prev. Cardiol. 16, 1775–1784 (2018) doi: 10.1177/2047487318790056

2. The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. U.S. Department of health and human services. National Institutes of Health (2005) Report

3. Ma, C. et al. Performance of eleven simplified methods for the identification of elevated blood pressure in children and adolescents. Hypertension 68, 614–620 (2016) doi: 10.1161/HYPERTENSIONAHA.116.07659