Association between pregnancy-related hypertension and severity of hypertension

A prospective study of arsenic and manganese exposures and maternal blood pressure during gestation

BACKGROUND

Pregnancy is a sensitive time for maternal cardiovascular functioning and exposures to arsenic or manganese may adversely affect blood pressure (BP).

OBJECTIVES

This study examined the associations between arsenic and manganese exposures and maternal BP measured during pregnancy. Effect modification by pre-pregnancy body mass index (BMI) was evaluated.

METHODS

Pregnant women (N = 1522) were recruited for a prospective cohort study in Bangladesh (2008-2011). Exposure to arsenic and manganese was measured in drinking water at <16 weeks gestation and toenails at one-month postpartum. Systolic and diastolic BP were measured monthly. Linear mixed models estimated mean BP and differences in mean BP over gestation for arsenic or manganese exposures and adjusted for covariates.

RESULTS

Arsenic levels had an increasing dose-response association with maternal BP after 25 weeks gestation. Effect modification was observed for BMI. Participants with lower BMI (<23 kg/m²) exposed to 50 μg/L arsenic had 2.83 mmHg (95% CI:1.74-3.92) greater mean systolic and 1.96 mmHg (95% CI: 1.02-2.91 mmHg) diastolic BP compared to those exposed to ≤ 1 μg/L arsenic at 40 weeks gestation. Participants with higher BMI (≥23 kg/m²) showed a greater mean systolic BP of 5.72 mmHg (95% CI: 3.18-8.27 mmHg) and diastolic BP change of 6.09 mmHg (95% CI: 4.02-8.16 mmHg) at 40 weeks gestation when exposed to 50 μg/L compared to ≤ 1 μg/L arsenic. Participants with lower BMI exposed to drinking water manganese in the 2nd quartile (181-573 μg/L) had 1.04 mmHg higher mean diastolic BP (95% CI: 0.01-2.07 mmHg) at 40 weeks gestation compared to those in the 1st quartile (0.5-180 μg/L).

CONCLUSION

Arsenic exposures during pregnancy were consistently associated with increased average maternal systolic and diastolic BP. The effect of manganese on BP was less consistent.

The Association Between Hypertensive Disorders in Pregnancy and the Risk of Developing Chronic Hypertension

Objective

This meta-analysis comprehensively evaluated the association between hypertensive disorders in pregnancy (HDP) and the risk of developing chronic hypertension and the associations between specific types of HDP, including preeclampsia (PE) and gestational hypertension (GH), and the risk of developing chronic hypertension.

Design

Systematic review and meta-analysis.

Data Sources

The PubMed, Embase and Cochrane Library databases were searched from inception to August 20, 2021.

Methods

Depending on heterogeneity, the combined odds ratio (OR) of the 95% confidence interval (CI) was obtained with a random-effects or fixed-effects model. We used meta-regression analysis to explore the sources of heterogeneity. We analyzed the OR value after adjusting for age and BMI at recruitment, prepregnancy BMI, age at first delivery, and other factors. Additionally, we evaluated the results of the subgroup analysis by the year of publication (&lt; 2016, ≥ 2016), study design, sample size (&lt; 500, ≥ 500), region (North and South America, Europe, and other regions) and NOS score (&lt; 7, ≥ 7).

Results

Our systematic review and meta-analysis comprehensively explored the relationships between HDP, GH, and PE and chronic hypertension. Twenty-one articles that included 634,293 patients were included. The results of this systematic review and meta-analysis suggested that women with a history of HDP are almost 3.6 times more likely to develop chronic hypertension than those without a history of HDP, women with a history of GH are almost 6.2 times more likely to develop chronic hypertension than those without a history of GH, and women with a history of PE are almost 3.2 times more likely to develop chronic hypertension than those without a history of PE. In addition, we further calculated the probability of developing chronic hypertension among patients with HDP or PE after adjusting for age and BMI at recruitment, prepregnancy BMI, age at first delivery, and other factors. The results suggested that women with a history of HDP are almost 2.47 times more likely to develop chronic hypertension than those without a history of HDP and that women with a history of PE are almost 3.78 times more likely to develop chronic hypertension than those without a history of PE. People in Asian countries are more likely to develop chronic hypertension after HDP or PE, while American people are not at high relative risk.

Conclusion

These findings suggest that HDP, GH, and PE increase the likelihood of developing chronic hypertension. After adjustment for age and BMI at recruitment, prepregnancy BMI, age at first delivery, and other factors, patients with HDP or PE were still more likely to develop chronic hypertension. HDP may be a risk factor for chronic hypertension, independent of other risk factors. GH and PE, as types of HDP, may also be risk factors for chronic hypertension.

Systematic Review Registration

[www.ClinicalTrials.gov], identifier [CRD42021238599].

Long-term effectiveness of non-drug recommendations to treat hypertension in a clinical setting

BACKGROUND

Nonpharmacological interventions have been efficacious to control blood pressure (BP) in clinical trials, but their long-term effectiveness in clinical practice was still not documented.

METHODS

This is a prospective cohort study of 825 patients who received repeated nonpharmacological recommendations to treat hypertension. The outcomes were BP change and rate of BP control by pattern of adherence (informed by the patients) to the recommendations to follow low-salt and low-calorie diets and to do physical activities.

RESULTS

Patients were followed for 23.1 ± 8.4 months. Between group deltas of BP change in patients with and without adherence to the low-salt diet, adjusted for baseline BP, body mass index (BMI), age, and number of drugs in use, were 5.1 (95% confidence interval: 1.7-8.6) mm Hg for systolic (P = 0.003) and 2.1 (0.2-3.9) mmHg for diastolic BP (P = 0.02). For adherence to low-calorie diet, the deltas were 6.6 (2.9-10.2) mm Hg (P < 0.001) and 2.0 (0.1-3.9) mm Hg (P = 0.045). Adherence to physical activities was not associated with a BP-lowering effect. Relative risks for a fall of 10 mm Hg in systolic or 5 mm Hg in diastolic BP, with adjustment for confounding, were 0.69 (95% confidence interval: 0.55-0.87) for adherence to the low-salt diet, 0.83 (0.66-1.05) for low-calorie diet, and 0.99 (0.79-1.24) for exercise.

CONCLUSIONS

Adherence to low-salt and low-calorie diets is associated with clinically relevant long-term BP reduction and better hypertension control in a clinical setting.

Low-level lead exposure and elevations in blood pressure during pregnancy

BACKGROUND

Lead exposure is associated with elevated blood pressure during pregnancy; however, the magnitude of this relationship at low exposure levels is unclear.

OBJECTIVES

Our goal was to determine the association between low-level lead exposure and blood pressure during late pregnancy.

METHODS

We collected admission and maximum (based on systolic) blood pressures during labor and delivery among 285 women in Baltimore, Maryland. We measured umbilical cord blood lead using inductively coupled plasma mass spectrometry. Multivariable models were adjusted for age, race, median household income, parity, smoking during pregnancy, prepregnancy body mass index, and anemia. These models were used to calculate benchmark dose values.

RESULTS

Geometric mean cord blood lead was 0.66 μg/dL (95% confidence interval, 0.61-0.70). Comparing blood pressure measurements between those in the highest and those in the lowest quartile of lead exposure, we observed a 6.87-mmHg (1.51-12.21 mmHg) increase in admission systolic blood pressure and a 4.40-mmHg (0.21-8.59 mmHg) increase in admission diastolic blood pressure after adjustment for confounders. Corresponding values for maximum blood pressure increase were 7.72 (1.83-13.60) and 8.33 (1.14-15.53) mmHg. Benchmark dose lower limit values for a 1-SD increase in blood pressure were < 2 μg/dL blood lead for all blood pressure end points.

CONCLUSIONS

A significant association between low-level lead exposures and elevations in maternal blood pressure during labor and delivery can be observed at umbilical blood lead levels < 2 μg/dL.