Maternal Hypertension Increases Risk of Preeclampsia and Low Fetal Birthweight:Genetic Evidence From a Mendelian Randomization Study

BACKGROUND: Maternal cardiovascular risk factors have been associated with adverse maternal and fetal outcomes. Given the difficulty in establishing causal relationships using epidemiological data, we applied Mendelian randomization to explore the role of cardiovascular risk factors on risk of developing pre-eclampsia or eclampsia, and low fetal birthweight. METHODS: Uncorrelated single nucleotide polymorphisms associated systolic blood pressure, body mass index, type 2 diabetes mellitus, low-density lipoprotein with cholesterol, smoking, urinary albumin-to-creatinine ratio and estimated glomerular filtration rate at genome-wide significance in studies of 298,957 to 1,201,909 European ancestry participants were selected as instrumental variables. A two-sample Mendelian randomization study was performed with primary outcome of pre-eclampsia or eclampsia (PET). Risk factors associated with PET were further investigated for their association with low birthweight. RESULTS: Higher genetically-predicted systolic blood pressure was associated increased risk of PET [odds ratio (OR) per 1-SD systolic blood pressure increase 1.90 (95% confidence interval (CI)1.45-2.49;p=3.23x10(-6) and reduced birthweight (OR=0.83; 95%CI=0.79-0.86;p=3.96x10(-18)), and this was not mediated by PET. Body mass index and type 2 diabetes were also associated with PET (respectively, OR per 1-SD body mass index increase=1.67 95%CI=1.44-1.94,;p=7.45x10(-12); and OR per logOR increase type 2 diabetes=1.11 95%CI=1.04-1.19p;=1.19x10(-3)), but not with reduced birthweight. CONCLUSIONS: Our results provide evidence for causal effects of systolic blood pressure, body mass index and type 2 diabetes on PET, and identify that systolic blood pressure is associated with reduced birthweight independently of PET. The results provide insight into the pathophysiological basis of PET and identify hypertension as a potentially modifiable risk factor amenable to therapeutic intervention

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Not AvailableThe study aims to elucidate the impact of organic inputs on strength and structural stability of aggregates in a sandy loam soil of Indo-Gangetic Plain Zone of India. Tensile strength, friability and water stability of aggregates, and the carbon contents in bulk soil and in large macro (>2 mm), small macro (0.25-2 mm), micro (0.053-0.25 mm) and silt+ clay size (<0.053) The aggregate were evaluated in soils with different sources and amounts of organic C inputs as partial substitution of N fertilizer. Addition of organic substrates significantly improved soil organic C contents, but the type and source of input had different impacts. Tensile strength of aggregates decreased and friability increased through organic inputs, with a maximum effect under rice residue-farmyard manure and wheat residue substitution.The aggregate strength and density were lower with organic substitution (p < 0.05) while water retention by aggregates at field capacity was 2–4% higher with organic inputs. Macro-aggregates (>0.25 mm) constituted 58–92% of water stable aggregates and varied significantly among treatments and soil depths. Organic material incorporation improved soil aggregation and structural stability and resulted in higher C content in macro-aggregates. Higher macro-aggregates in the crop residue- and farmyard manure-treated soils resulted in a higher aggregate mean weight diameter, which also had higher soil organic C contents. The bulk soil organic C had a strong relation with the mean weight diameter of aggregates, but the soil organic c content in all aggregate fractions was not necessarily effective for aggregate stability. The soil organic C content in large macro-aggregates (2-8mm) had a significant positive effect on aggregate stability, although a reverse effect was observed for aggregates<0.25 mm. Partial substitution of nitrogen by organic substrates improved aggregate properties and the soil organic C content in bulk soil and aggregate fractions, although the relative effect varied with the source and amount of the organic inputsNot Availabl