Nighttime blood pressure and nocturnal dipping are associated with daytime urinary sodium excretion in African subjects

Blood pressure (BP) follows a circadian rhythm, with 10% to 15% lower values during nighttime than during daytime. The absence of a nocturnal BP decrease (dipping) is associated with target organ damage, but the determinants of dipping are poorly understood. We assessed whether the nighttime BP and the dipping are associated with the circadian pattern of sodium excretion. Ambulatory BP and daytime and nighttime urinary electrolyte excretion were measured simultaneously in 325 individuals of African descent from 73 families. When divided into sex-specific tertiles of day:night ratios of urinary sodium excretion rate, subjects in tertile 1 (with the lowest ratio) were 6.5 years older and had a 9.8-mm Hg higher nighttime systolic BP (SBP) and a 23% lower SBP dipping (expressed in percentage of day value) compared with subjects in tertile 3 (P for trend <0.01). After adjustment for age, the SBP difference across tertiles decreased to 5.4 mm Hg (P=0.002), and the SBP dipping difference decreased to 17% (P=0.05). A similar trend across tertiles was found with diastolic BP. In multivariate analyses, daytime urinary sodium and potassium concentrations were independently associated with nighttime SBP and SBP dipping (P<0.05 for each). These data, based on a large number of subjects, suggest that the capacity to excrete sodium during daytime is a significant determinant of nocturnal BP and dipping. This observation may help us to understand the pathophysiology and clinical consequences of nighttime BP and to develop therapeutic strategies to normalize the dipping profile in hypertensive patients.     

Prevalence of obesity and overweight and associated nutritional factors in a population-based Swiss sample: an opportunity to analyze the impact of three different European cultural roots

Purpose

Obesity represents a growing public health concern worldwide. The latest data in Switzerland rely on self-reported body mass index (BMI), leading to underestimation of prevalence. We reassessed the prevalence of obesity and overweight in a sample of the Swiss population using measured BMI and waist circumference (WC) and explored the association with nutritional factors and living in different linguistic-cultural regions.

Methods

Data of 1,505 participants of a cross-sectional population-based survey in the three linguistic regions of Switzerland were analyzed. BMI and WC were measured, and a 24-h urine collection was performed to evaluate dietary sodium, potassium and protein intake.

Results

The prevalence of overweight, obesity and abdominal obesity was 32.2, 14.2 and 33.6 %, respectively. Significant differences were observed in the regional distribution, with a lower prevalence in the Italian-speaking population. Low educational level, current smoking, scarce physical activity and being migrant were associated with an higher prevalence of obesity. Sodium, potassium and protein intake increased significantly across BMI categories.

Conclusions

Obesity and overweight affect almost half of the Swiss adolescents and adults, and the prevalence appears to increase. Using BMI and WC to define obesity led to different prevalences. Differences were furthermore observed across Swiss linguistic-cultural regions, despite a common socio-economic and governmental framework. We found a positive association between obesity and salt intake, with a potential deleterious synergistic effect on cardiovascular risk.     

Sex difference and the role of leptin in the association between high-sensitivity C-reactive protein and adiposity in two different populations

Elevated high-sensitivity C-reactive protein (hs-CRP) concentration is associated with an increased risk of cardiovascular disease but this association seems to be largely mediated via conventional cardiovascular risk factors. In particular, the association between hs-CRP and obesity has been extensively demonstrated and correlations are stronger in women than men. We used fractional polynomials--a method that allows flexible modeling of non linear relations--to investigate the dose/response mathematical relationship between hs-CRP and several indicators of adiposity in Caucasians (Switzerland) and Africans (Seychelles) surveyed in two population-based studies. This relationship was non-linear exhibiting a steeper slope for low levels of hs-CRP and a higher level in women. The observed sex difference in the relationship between hs-CRP and adiposity almost disappeared upon adjustment for leptin, suggesting that these sex differences might be partially mediated, by leptin. All these relationship were similar in Caucasians and Africans. This is the first report on a non-linear relation, stratified by gender, between hs-CRP and adiposity.     

A new measurement of the half-life of (166m)Ho

The work presented here is a new and precise measurement of the half-life of (166m)Ho by determining the activity concentration, using an ionisation chamber calibrated for this nuclide, and measuring the number of (166m)Ho atoms using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). Since the isotope (166)Er interferes with the mass spectrometric measurement, Er has to be eliminated from the (166m)Ho radioactive solution. The elimination was achieved using ion-exchange chromatography with the cation exchange resin Dowex AG 50W-X8 and 2-Hydroxybutanoic acid as the mobile phase. After a first transit through the chromatographic column, the purified (166m)Ho eluate was spiked with natural Er to get a resulting Er isotopic composition close to that of natural Er at better than 99.5%, and then it underwent two further separations to eliminate the Er. The activity concentration of this Er-free radioactive (166m)Ho solution was measured in our reference ionisation chamber calibrated for this nuclide by means of the 4πβ(PC)-γ and 4πβ(PS)-4πγ coincidence techniques and integral counting with a well-type NaI(Tl) detector and Monte Carlo efficiencies. An aliquot of this standardized solution was sent to the Paul Scherrer Institute (PSI) for mass concentration determination using an isotope dilution MC-ICP-MS approach. The mass concentration of (166m)Ho in this solution was determined with 0.25% relative standard uncertainty. This value was corroborated by two other independent measurements. The new half-life of (166m)Ho, 1132.6(39) years (k=1), is compatible with the value determined in 1965, but is 5.6% shorter and about 43 times more precise.     

Predictors of maternal mortality in institutional deliveries in Nigeria

Background

Maternal mortality in poor countries reflects the under-development in these societies. Global recognition of the burden of maternal mortality and the urgency for a reversal of the trend underpin the Millenium Development Goals (MDGs).

Objective

To determine risk factors for maternal mortality in institutional births in Nigeria.

Method

Twenty one health facilities in three states were selected using stratified multi-stage cluster sampling strategy. Information on all delivered mothers and their newborn infants within a three-month period was culled from medical records.

Results

A total of 9 208 deliveries were recorded. About one-fifth (20.5%) of women had no antenatal care while 79.5% had at least one antenatal visit during pregnancy. Four-fifths (80.5%) of all deliveries were normal deliveries. Elective and emergency caesarean section rates were 3.1% and 11.5% respectively. There were 79 maternal deaths and 8 526 live births, giving a maternal mortality ratio of 927 maternal deaths per 100 000 live births. No antenatal care, parity, level of education, and mode of delivery were significantly associated with maternal mortality. Low maternal education, high parity, emergency caesarean delivery, and high risk patients risk independently predicted maternal mortality.

Conclusion

Meeting goal five of the MDGs remains a major challenge in Nigeria. Multi-sectoral approaches and focused political will are needed to revert the high maternal mortality.