Hypertension: Landau LI

Anonymous00047, Fitzgerald DA, Massie RJ, Nixon GM, Jaffe A, Wilson A, Landau LI, Twiss J, Smith G, Wainwright C, Harris M. · Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, NSW, Australia. · Med J Aust. · Pubmed #19012558 links to  free full text

Abstract: Chronic neonatal lung disease (CNLD) is defined as a supplemental oxygen requirement beyond 36 weeks' postmenstrual age, with more severely affected infants requiring oxygen beyond a full-term-equivalent age. Low-flow supplemental oxygen facilitates discharge from hospital of infants with CNLD who develop hypoxia in air. There is a lack of data on the most appropriate minimum mean target oxygen saturation (Spo(2)) level. Reflecting a variety of clinical practices and infant comorbidities (frequency of oxygen desaturation, presence of pulmonary hypertension, retinopathy of prematurity, and adequacy of growth), the minimum mean target range for Spo(2) during overnight oximetry should be 93%-95%. The effect of supplemental oxygen on carbon dioxide retention should be considered before deciding on an oxygen flow. Most infants with CNLD are not ready for discharge until their supplemental oxygen requirement is < or = 0.5 litres per minute delivered through a nasal cannula. The safety of short-term disconnection from supplemental oxygen should be assessed before discharge. Assessment of oxygenation during sleep with continuous overnight oximetry or polysomnography is recommended when weaning infants from supplemental oxygen. Discontinuation of oxygen therapy is based on clinical assessments and documentation of adequate oxygenation in room air. There is limited objective evidence on which to base recommendations.

Huang RC, Burke V, Newnham JP, Stanley FJ, Kendall GE, Landau LI, Oddy WH, Blake KV, Palmer LJ, Beilin LJ. · School of Medicine and Pharmacology, The University of Western Australia (UWA) (M570), Royal Perth Hospital, Perth, Western Australia, Australia. · Int J Obes (Lond). · Pubmed #16718281 No free full text.

Abstract: BACKGROUND: Features of the metabolic syndrome comprise a major risk for cardiovascular disease and will increase in prevalence with rising childhood obesity. We sought to identify early life influences on development of obesity, hypertension and dyslipidemia in children. METHODS AND RESULTS: Cluster analysis was used on a subset of a longitudinal Australian birth cohort who had blood samples at age 8 (n=406). A quarter of these 8-year-olds fell into a cluster with higher body mass index, blood pressure (BP), more adverse lipid profile and a trend to higher serum glucose resembling adult metabolic syndrome. There was a U-shaped relationship between percentage of expected birth weight (PEBW) and likelihood of being in the high-risk cluster. The high-risk cluster had elevated BP and weight as early as 1 and 3 years old. Increased likelihood of the high-risk cluster group occurred with greatest weight gain from 1 to 8 years old (odds ratio (OR)=1.4, 95% confidence interval (CI)=1.3-1.5/kg) and if mothers smoked during pregnancy (OR=1.82, CI=1.05-3.2). Risk was lower if children were breast fed for >/=4 months (OR=0.6, 95% CI=0.37-0.97). Newborns in the upper two quintiles for PEBW born to mothers who smoked throughout pregnancy were at greatest risk (OR=14.0, 95% CI=3.8-51.1) compared to the nadir PEBW quintile of non-smokers. CONCLUSION: A U-shaped relationship between birth weight and several components of the metabolic syndrome was confirmed in a contemporary, well-nourished Western population of full-term newborns, but post-natal weight gain was the dominant factor associated with the high-risk cluster. There was a prominence of higher as well as lowest birth weights in those at risk. Future health programs should focus on both pre- and post-natal factors (reducing excess childhood weight gain and smoking during pregnancy), and possibly the greatest benefits may arise from targeting the heaviest, as well as lightest newborns, especially with a history of maternal smoking during pregnancy.

Burke V, Beilin LJ, Blake KV, Doherty D, Kendall GE, Newnham JP, Landau LI, Stanley FJ. · The University of Western Australia, School of Medicine and Pharmacology, Royal Perth Hospital and Western Australian Institute for Medical Research, Perth, Australia. · Hypertension. · Pubmed #14718353 links to  free full text

Abstract: Inverse associations between size at birth and blood pressure (BP) in later life are commonly statistically significant only after adjustment for current size, consistent with change in size as the determinant. Few studies have been prospective or have included a range of potential confounders. Using regression models, including maternal and demographic variables, we examined associations between size at birth and BP in Australian children followed from week 16 of gestation to the age of 8 years. BP measurements were available from 1417 children born after 37 weeks gestation without congenital abnormalities. In models adjusted only for sex, the birthweight (BW), birth length, ponderal index, head circumference, chest circumference, abdominal girth, mid-arm circumference, triceps skinfold, placental weight, or BW/placental weight ratio did not significantly predict SBP in 8-year-olds. With adjustment for current size, associations were inverse but not statistically significant (regression coefficients: BW, -1.11; 95% confidence limits [CL], -2.22, 0.01; birth length, -0.25; 95% CL, -0.52, 0.24) and remained nonsignificant after adjustment for confounders. Current weight, height, or body mass index significantly predicted SBP and DBP (P<0.001) with differences of 8/4 mm Hg between upper and lower quartiles; effects were similar in infants with lower and higher BW. These findings are consistent with postnatal change in size as the major determinant of BP in 8-year-olds and are important in the context of the worldwide "epidemic" of obesity in childhood as a likely precursor of increasing rates of hypertension in adults.

Blake KV, Gurrin LC, Beilin LJ, Stanley FJ, Landau LI, Newnham JP. · Department of Obstetrics and Gynaecology, King Edward Memorial Hospital, Subiaco, Western Australia. · J Hypertens. · Pubmed #11330872 No free full text.

Abstract: OBJECTIVE: A significant inverse relationship between blood pressure and birth weight is firmly established. This association may be the result of fetal adaptations to an adverse intrauterine environment. Further markers of intrauterine growth include the weight of the placenta and the placental ratio (the ratio of placental weight to birth weight). A number of studies suggest that a decreased placental weight or an elevated placental ratio may be independent risk factors for subsequent high blood pressure. The overall evidence for this is, however, inconclusive. The purpose of the present study was to clearly define the relationships between placental weight, placental ratio and subsequent blood pressure during childhood. DESIGN: Prospective cohort study of 2507 singleton children, born at term during 1989-1992. Blood pressures were recorded at ages 1, 3 and 6 years, using a semi-automated oscillometric device. RESULTS: Inverse relationships existed between both systolic and diastolic blood pressure and placental weight, adjusted for current weight at ages 1, 3 and 6 years. The relationships between placental weight and systolic blood pressure were statistically significant at ages 1 and 3 years. There was no consistent relationship between placental weight and later blood pressure within birth weight categories. No clinically or statistically significant association was seen between the placental ratio and either systolic or diastolic blood pressures at any age. CONCLUSIONS: Birth weight, rather than placental weight or their ratio, is the early life factor most importantly related to subsequent blood pressure in childhood.