Inverse association between obesity and aortic pressure augmentation is attenuated in women: the Wakuya study.

OBJECTIVE: Pressure wave reflection predicts cardiovascular events in the general population. Obesity is negatively associated with pressure wave reflection. Muscular arterial diameter (responsible for pressure wave reflection) increases with obesity, and obesity-dependent dilation of muscular arteries is attenuated in women compared with men. We investigated the sex differences in the cross-sectional relationship between obesity and pressure wave reflection in a general population cohort. METHODS: Tonometric pressure waveforms were recorded in 928 adults (mean age, 56 ±â€Š10 years) to estimate the aortic augmentation index. The BMI was calculated using height and body weight, and waist circumference was recorded at the umbilical level. RESULTS: Aortic augmentation index was significantly higher in women than in men. Indices of obesity (BMI and waist circumference) were negatively correlated with the aortic augmentation index in both men and women, even after adjusting for mean arterial pressure (both P  < 0.001). Sex and BMI had no synergistic effect on the aortic augmentation index. However, when waist circumference was substituted for BMI, sex and waist circumference had a reciprocal influence on decreasing the aortic augmentation index independent of age, mean arterial pressure, diabetes, and hyperlipidemia (interaction, P  = 0.045). CONCLUSION: The negative correlation between overweight/obesity and aortic pressure augmentation from peripheral wave reflection is inhibited in women more than in men. Sex differences in aortic pressure augmentation are greater in individuals with central (abdominal) obesity than in those with general obesity.

Being overweight worsens the relationship between urinary sodium excretion and albuminuria: the Wakuya study.

BACKGROUND/OBJECTIVES: (Micro)albuminuria (a manifestation of renal microvascular damage) is an independent predictor of mortality risk, even when the urinary albumin/creatinine ratio is ≥ 10 mg/g in the general population. Excessive sodium intake and obesity are strong predictors of cardiovascular disease. However, the effect of obesity on the relationship between sodium intake and albuminuria is not fully understood. SUBJECTS/METHODS: The purpose of the present study was to investigate the cross-sectional relationships among dietary sodium intake, obesity, and albuminuria in a general population cohort. Subjects were 928 apparently healthy adults. Body mass index was calculated using the height and body weight. Urinary sodium/creatinine and albumin/creatinine ratios were measured in spot urine samples. Estimated 24-h urinary sodium/creatinine ratio (e24UNa/Cr) was assessed using age, height, body weight, and spot urinary sodium/creatinine ratio. RESULTS: Both the body mass index and e24UNa/Cr positively correlated with the urinary albumin/creatinine ratio (both, P < 0.001), and had a synergistic effect on increasing urinary albumin/creatinine ratio independent of age, sex, mean arterial pressure, and diabetes (interaction P = 0.04). When subjects were divided into 6 groups according to the tertiles of e24UNa/Cr and body mass index < (normal-weight) or ≥ 25 (overweight), the prevalence rate of urinary albumin/creatinine ratio ≥ 10 mg/g increased with rising e24UNa/Cr and being overweight (P < 0.001). CONCLUSION: An increase in body mass index increases the positive association between urinary sodium excretion and (micro)albuminuria in the general population. Excess sodium intake may strengthen cardiovascular risk by increasing (micro)albuminuria, particularly in overweight individuals.

Aortic diastolic pressure decay explains sex-related differences in the subendocardial viability ratio: the Wakuya study.

OBJECTIVE: Coronary heart disease is the leading cause of mortality in women. Despite a higher risk of heart failure after the first myocardial infarction in women compared with men, the sex-specific mechanisms are unknown. We hypothesized that myocardial ischemia is attributable to sex-related diastolic alterations in the central hemodynamics. METHODS: We investigated the subendocardial viability ratio (myocardial oxygen supply/demand) and aortic diastolic pressure decay index in 962 apparently healthy adults (mean age, 56 ±â€Š10 years). Using noninvasive applanation tonometry, the subendocardial viability ratio, aortic diastolic pressure decay index, and aortic augmentation index were estimated in all participants. The aortic diastolic pressure decay index was quantified by fitting an exponential curve: P(t) = P0e-λt (λ, decay index; P0, end-systolic pressure; t, time from end-systole). RESULTS: Women showed a significantly higher aortic diastolic pressure decay index, even after adjusting for age, hypercholesterolemia, and diabetes, and a significantly lower subendocardial viability ratio than men (P < 0.001). Analysis demonstrated a mediating effect of the aortic decay index on the sex-related differences in the subendocardial viability ratio (71%), despite different effects of the augmentation index (5%). CONCLUSION: These results suggest that the predisposition of women to coronary heart disease is more likely attributable to impaired myocardial perfusion caused by accelerated aortic diastolic pressure decay, rather than increased myocardial load due to augmented aortic systolic pressure.

Albuminuria Intensifies the Link Between Urinary Sodium Excretion and Central Pulse Pressure in the General Population: The Wakuya Study.

BACKGROUND: Central pulse pressure (cPP) is responsible for the hemodynamics of vital organs, and monitoring this parameter is important for cardiovascular disease (CVD) prevention. Excess sodium intake and (micro)albuminuria (a manifestation of renal microvascular damage) are known to be strong predictors of CVD. We sought to investigate the cross-sectional relationships among dietary sodium intake, albuminuria, and cPP in a general population cohort. METHODS: The subjects were 933 apparently healthy adults (mean age, 56 ± 10 years). Radial pressure waveforms were recorded with applanation tonometry to estimate mean arterial pressure (MAP), cPP, forward and backward pressure amplitudes, and augmentation index. The urinary sodium/creatinine and albumin/creatinine ratios were measured in spot urine samples. RESULTS: Both the urinary sodium/creatinine and albumin/creatinine ratios were positively correlated with cPP, even after adjusting for MAP (P < 0.001). Moreover, both ratios had a synergistic influence on increasing the cPP independent of age, sex, estimated glomerular filtration rate, hyperlipidemia, and diabetes (interaction P = 0.04). A similar synergistic influence was found on the forward pressure amplitude, but not on the backward pressure amplitude or augmentation index. The overall results were not altered when the urinary albumin/creatinine ratio was replaced with the existence of chronic kidney disease (CKD). CONCLUSIONS: (Micro)albuminuria strengthens the positive association between urinary sodium excretion and cPP and systolic forward pressure. Excess sodium intake may magnify the cardiovascular risk by widening the aortic pulsatile pressure, particularly in the presence of concomitant CKD.