Childhood Determinants of Future Blood Pressure

Theodore RF, Broadbent J, Nagin D, et al. Childhood to early-midlife systolic blood pressure trajectories: early-life predictors, effect modifiers, and adult cardiovascular outcomes. Hypertension. 2015; 66(6): 1108– 1115; doi: 10.1161/HYPERTEN-SIONAHA.115.05831Investigators from multiple international institutions conducted a prospective cohort study to track blood pressure (BP) trajectories from childhood to adulthood, and identify risk factors and potential modifiers of high BP and their association with future cardiovascular (CV) risk. A single cohort of New Zealand individuals, born during 1972 and 1973, members of a longitudinal, multidisciplinary health study, participated in the present study. BP, weight, and height measurements were taken at ages 7, 11, 18, 26, 32, and 38 years. Using specialized statistical software and BP measurement results from these ages (ie, from 7 years to 38 years), each participant was placed into 1 of 4 BP group trajectories (normal, high-normal, pre-hypertensive, and hypertensive. Information related to birth, family, social, and medical history was obtained at the various examination points. At age 38, waist/hip ratio, lipid panel, and glycohemoglobin levels were obtained. Multivariate regression analyses were conducted to identify various characteristics associated with being in the higher BP trajectory groups.A total of 913 individuals were included in analysis. Among this cohort, 21.8% were categorized as normotensive, 43.3% as having high-normal BP, 31.6% as pre-hypertensive, and 4.2% as hypertensive. The hypertensive group had the highest mean BP at age 7, as well as the steepest rise in BP by age 38. Male sex, family history of hypertension (HTN), having a mother with pregnancy-induced HTN, being first-born, and lower birth weight were statistically associated with an individual being in a higher BP group than the normal BP trajectory group. Increasing body mass index (BMI) was associated with higher BP, and this effect was strongest over time in the pre-hypertensive and hypertensive groups. Cigarette smoking had a similar relationship with BP groups. When the association between BP groups and CV risk indicators (waist/hip ratio, lipids, glycohemoglobin) were analyzed, higher BP groups were generally found to have higher levels of these markers.The authors conclude that early BP values can predict BP values later in life, and that those with higher BP have higher levels of other CV risk indicators.Dr Singer has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.The massive health care burden on the US population from HTN is well known. The CDC estimates that 29% of American adults have HTN, and a similar percentage of adults are pre-hypertensive. The total estimated cost of HTN is $46 billion per year, from medical costs and missed work days.1 Elevated BP affects the pediatric population as well, with studies estimating 9.6% of children with “elevated BP” and another 1.6% with HTN.2 Although multiple studies have indicated that childhood BP tracks into adulthood,3 a controversial 2013 US Preventive Services Task Force statement determined there was inadequate evidence to recommend universal BP screening in children, based in part on a lack of data showing that childhood BP screening accurately identified individuals at risk for adult HTN and CV.4 The current study aims to bridge this data gap by providing long-term tracking of childhood BP at multiple data points, and, in addition, by correlating BP with other markers of CV risk. The study confirms the association of many well-known risk factors with BP, most notably BMI. It demonstrates an association between higher BP category and other markers of CV risk, namely lipids and glycohemoglobin. However, one of the study’s major limitations is the lack of biochemical data points prior to the 38-year study visit, thereby casting doubt on the true causality of these associations. In addition, these are surrogate markers and may or may not accurately reflect the overall CV risk in each group. Nevertheless, the demonstration of clear BP tracking from childhood to adulthood adds to the body of evidence supporting the use of BP measurement in children. As more long-term data become available, studies directly assessing the link between childhood BP and CV mortality will be crucial to elucidate this relationship.