Correlation of serum DKK1 level with skeletal phenotype in children with osteogenesis imperfecta

PURPOSE

We aim to detect serum DKK1 level of pediatric patients with OI and to analyze its relationship with the genotype and phenotype of OI patients.

METHODS

A cohort of pediatric OI patients and age-matched healthy children were enrolled. Serum levels of DKK1 and bone turnover biomarkers were measured by enzyme-linked immunosorbent assay. Bone mineral density (BMD) was measured by Dual-energy X-ray absorptiometry. Pathogenic mutations of OI were detected by next-generation sequencing and confirmed by Sanger sequencing.

RESULTS

A total of 62 OI children with mean age of 9.50 (4.86, 12.00) years and 29 healthy children were included in this study. The serum DKK1 concentration in OI children was significantly higher than that in healthy children [5.20 (4.54, 6.32) and 4.08 (3.59, 4.92) ng/mL, P < 0.001]. The serum DKK1 concentration in OI children was negatively correlated with height (r = - 0.282), height Z score (r = - 0.292), ALP concentration (r = - 0.304), lumbar BMD (r = - 0.276), BMD Z score of the lumbar spine and femoral neck (r = - 0.32; r = - 0.27) (all P < 0.05). No significant difference in serum DKK1 concentration was found between OI patients with and without vertebral compression fractures. In patients with spinal deformity (22/62), serum DKK1 concentration was positively correlated with SDI (r = 0.480, P < 0.05). No significant correlation was observed between serum DKK1 concentration and the annual incidence of peripheral fractures, genotype and types of collagen changes in OI children.

CONCLUSION

The serum DKK1 level was not only significantly elevated in OI children, but also closely correlated to their skeletal phenotype, suggesting that DKK1 may become a new biomarker and a potential therapeutic target of OI.

High prevalence of vertebral deformity in tumor-induced osteomalacia associated with impaired bone microstructure

PURPOSE

Patients with tumor-induced osteomalacia (TIO) often suffer from irreversible height loss due to vertebral deformity. However, the prevalence of vertebral deformity in TIO patients varies among limited studies. In addition, the distribution and type of vertebral deformity, as well as its risk factors, remain unknown. This study aimed to identify the prevalence, distribution, type and risk factors for vertebral deformity in a large cohort of TIO patients.

METHODS

A total of 164 TIO patients were enrolled in this retrospective study. Deformity in vertebrae T4-L4 by lateral thoracolumbar spine radiographs was evaluated according to the semiquantitative method of Genant. Bone microstructure was evaluated by trabecular bone score (TBS) and high-resolution peripheral QCT (HR-pQCT).

RESULTS

Ninety-nine (99/164, 60.4%) patients had 517 deformed vertebrae with a bimodal pattern of distribution (T7-9 and T11-L1), and biconcave deformity was the most common type (267/517, 51.6%). Compared with patients without vertebral deformity, those with vertebral deformity had a higher male/female ratio, longer disease duration, more height loss, lower serum phosphate, higher bone turnover markers, lower TBS, lower areal bone mineral density (aBMD), lower peripheral volumetric BMD (vBMD) and worse microstructure. Lower trabecular vBMD and worse trabecular microstructure in the peripheral bone and lower spine TBS were associated with an increased risk of vertebral deformity independently of aBMD. After adjusting for the number of deformed vertebrae, we found little difference in clinical indexes among the patients with different types of vertebral deformity. However, we found significant correlations of clinical indexes with the number of deformed vertebrae and the spinal deformity index.

CONCLUSION

We reported a high prevalence of vertebral deformity in the largest cohort of TIO patients and described the vertebral deformity in detail for the first time. Risk factors for vertebral deformity included male sex, long disease duration, height loss, abnormal biochemical indexes and bone impairment. Clinical manifestation, biochemical indexes and bone impairment were correlated with the number of deformed vertebrae and degree of deformity, but not the type of deformity.

Genotype-phenotype relationship and comparison between eastern and western patients with osteogenesis imperfecta

PURPOSE

To evaluate the genotypic and phenotypic relationship in a large cohort of OI patients and to compare the differences between eastern and western OI cohorts.

METHODS

A total of 671 OI patients were included. Pathogenic mutations were identified, phenotypic information was collected, and relationships between genotypes and phenotypes were analyzed. Literature about western OI cohorts was searched, and differences were compared between eastern and western OI cohorts.

RESULTS

A total of 560 OI patients were identified as carrying OI pathogenic mutations, and the positive detection rate of disease-causing gene mutations was 83.5%. Mutations in 15 OI candidate genes were identified, with COL1A1 (n = 308, 55%) and COL1A2 (n = 164, 29%) being the most common mutations, and SERPINF1 and WNT1 being the most common biallelic variants. Of the 414 probands, 48.8, 16.9, 29.2 and 5.1% had OI types I, III, IV and V, respectively. Peripheral fracture was the most common phenotype (96.6%), and femurs (34.7%) were most commonly affected. Vertebral compression fracture was observed in 43.5% of OI patients. Biallelic or COL1A2 mutation led to more bone deformities and poorer mobility than COL1A1 mutation (all P < 0.05). Glycine substitution of COL1A1 or COL1A2 or biallelic variants led to more severe phenotypes than haploinsufficiency of collagen type I α chains, which induced the mildest phenotypes. Although the gene mutation spectrum varied among countries, the fracture incidence was similar between eastern and western OI cohorts.

CONCLUSION

The findings are valuable for accurate diagnosis and treatment of OI, mechanism exploration and prognosis judgment. Genetic profiles of OI may vary among races, but the mechanism needs to be explored.

PTH level might be associated with impaired quality of life in patients with nonsurgical hypoparathyroidism

OBJECTIVE

Nonsurgical hypoparathyroidism (ns-HP) is a rare disease. There are few studies on Quality of Life (QoL) among patients with ns-HP. This study aimed to investigate the QoL among ns-HP patients with regular conventional treatment, and explore the influence factors affecting QoL among these Chinese ns-HP patients.

METHODS

This is a cross-sectional study comparing 101 patients identified as ns-HP and 101 healthy controls. The questionnaires of Short Form 36 Health Survey questionnaire version 2(SF-36v2) were used to evaluate QoL.

RESULTS

Scores of all eight subdomains of SF-36v2 and physical component scores (PCS), mental component scores (MCS) were significantly lower in the ns-HP group compared with the healthy controls. The indices of all subdomains of SF-36v2 between Q1 (the lowest quartile) and Q4 (the highest quartile) groups were compared, suggesting higher percentages of detectable parathyroid hormone (PTH) before treatment in Q4 group among all QoL indices except two subdomains (physical function and body pain).

CONCLUSION

Both mental and physical QoL were impaired in the ns-HP patients even with regular conventional treatment for hypocalcemia, which were more severe in cases with lower baseline PTH levels.

[The diagnosis of primary hyperparathyroidism--analysis of 134 cases]

This article reports the diagnostic experiences of 134 cases of primary hyperparathyroidism (PHPT) confirmed by operation and pathologic examination. The clinical presentations were divided into 4 types: (1) 75 cases (56.0%) with bone resorption; (2) 47 cases (35.0%) with bone lesions plus urinary calculus; (3) 8 cases (6.0%) with urinary calculus only and; (4) 4 cases (3.0%) with hypercalcemia only. Bone lesions included bone resorption, osteomalacia and osteoporosis. Stones at multiple sites in the urinary tract or nephrocalcinosis were found in 41 cases. The measurement of ionized calcium was much more sensitive and accurate than the total calcium assay with the positive rate of 95.3% and 73.4% respectively. The concentration of plasma iPTH was high in the whole group (n = 84), the mean value was 21.4 +/- 17.9 times higher than that of the normal control group. For the localization of the affected parathyroid gland, instiat examination was by neck ultrasonography which gone a positive predictive value of 81.5% (43/53), 99mTc-MIBI scan showed positive rate 94.1% (16/17). The CT scan of the chest was used when ectopic location in mediastinum was highly suspected. If the first operative exploration failed to find the affected parathyroid gland, we performed the determinations of iPTH with samples taken from internal jugular vein through selective venous catheterization; the coincidence rate was found to be 85.2% (23/27).

[Comparative study on tissue morphology and vascular changes of skin xenografts, allografts and autografts after transplantation]

In this study, the tissue morphology and the vascular changes of skin xenografts from the rats to the rabbits were compared with that of skin allografts and autografts simultaneously transplanted to the same recipient by the use of histological examination and dye injection. The results suggested that the xenografts were incapable of becoming vascularized, and exhibited necrosis on the third day, while early vascularization was demonstrated in the allografts and autografts. The xenografts underwent a course of "white graft rejection", which probably contributed to rejection.

[The association between vitamin D receptor gene polymorphisms, bone mineral density and osteocalcin in Chinese women]

OBJECTIVE

To investigate the correlations between vitamin D receptor (VDR) gene polymorphisms, and bone mineral density (BMD) as well as osteocalcin.

METHODS

We used PCR-RFLP and Southern hybridization analysis to determine VDR genotypes in 202 Chinese women. BMD was measured by dual-energy X-ray absorptiometry (DEXA) and serum osteocalcin level was determined by radioimmunoassay. Analysis of covariance was used to test differences in mean BMDs across genotypes.

RESULTS

We realized that VDR genotype frequencies in Chinese women were apparently different from those of Caucasians. In group of postmenopausal women, "bb" or "aa" genotype was related to lower BMD in Femoral Neck and Trochanter. No association was found between VDR genotypes and the serum osteocalcin level.

CONCLUSION

There was some association between VDR genotypes and BMD in Chinese women. Its function in predicting osteoporosis still requires further study.

[Studies on the antimould activity of compound TBZ and its application in paint]

The compound TBZ is a new antimould agent, which contains mainly [2-(4-thiazolyl) benzoimidazole (TBZ)], ethanoic acid and propionic acid. It was shown in laboratory experiment that the compound TBZ had excellent mycostatic effect on all the 10 fungi tested with 70% of the mycostatic zones larger than 6.0 cm. It had obvious inhibitary activity on Alternaria Nees and Aureobasidium Pullulans isolated from mouldy wall. In laboratory condition the surface of fibreboard painted with compound TBZ did not become mouldy in 120 days, while the 20% of that coated with TBZ directly mixed in the paint became mouldy. In practical use, the antimould effect of the wall painted with compound TBZ could maintain more than two years.

The efficacy and safety of different doses of calcitriol combined with neutral phosphate in X-linked hypophosphatemia: a prospective study

The present study was the first prospective cohort evaluated the efficacy and safety of different doses of calcitriol in XLH children. The results suggested that a dose of 40 ng/kg/day calcitriol, compared with 20 ng/kg/day, was more effective in relieving the rickets, with similar safety outcomes. Further investigations were expected to set more dose groups.

INTRODUCTION

Dose recommended for calcitriol in X-linked hypophosphatemia (XLH) varies in different studies. Therefore, we aimed to compare the efficacy as well as the safety of 20 ng/kg/d and 40 ng/kg/d calcitriol in Chinese XLH pediatrics population.

METHODS

A 2-year, randomized, open-label, prospective study recruited 68 XLH children, which were randomized to receive either 40 ng/kg/day or 20 ng/kg/day calcitriol. Efficacy endpoints were the total Thacher ricket severity score (RSS) change from baseline to month 12 and 24, the difference in serum TALP level, fasting serum phosphate level, body height Z-score, and frequency of dental abscess. Safety assessments were done using renal ultrasound nephrocalcinosis grades (0-4), fasting serum and 24 h urine calcium level, and the occurrence of hyperparathyroidism.

RESULTS

The decrease in the total RSS from baseline was more significant in the high-dose group at 12 (difference 0.87, p = 0.049) and 24 month (difference 1.23, p = 0.011). The serum TALP level was significantly lower in the high-dose group at 6 months. Pi level, height Z-score change, frequency of dental abscess and ratio of de novo nephrocalcinosis were comparable. A lower incidence of secondary hyperparathyroidism was seen in the high-dose group (p < 0.0001).

CONCLUSION

For the first time in this prospective cohort, 40 ng/kg/d calcitriol was shown to be the more effective therapy in XLH children than the 20 ng/kg/d. Moreover, 40 ng/kg/d calcitriol was not associated with increasing adverse events.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT 03,820,518.

[Clinical observation of phacoemulsification with foldable intraocular lens implantation through a limbus incision]

OBJECTIVE

To investigate the clinical therapeutic effects of phaco-emulsification with foldable intraocular lens implantation through a limbus tunnel incision.

METHODS

Eighty-six patients (107 eyes) with senile cataract underwent phacoemulsification with acrylic foldable posterior chamber intraocular lens implantation through a 4 mm superior limbus tunnel incision.

RESULTS

The corrected visual acuity of 0.5 or better was 62.6% at the 1st day, and 76.6%, 92.5% and 88.8% respectively at the 1st week, 1st month and 3rd month postoperatively.

CONCLUSION

Phacoemulsification with foldable intraocular lens implantation through a limbus tunnel incision has advantages of both scleral tunnel incision and clear corneal tunnel incision. The postoperative therapeutic effects are satisfactory.

[Effects of alfacalcidol on osteoporosis in ovariectomized rats]

OBJECTIVE

To investigate the effects of alfacalcidol on osteoporosis in rats induced by ovariectomy (OVX).

METHODS

Fifty-three virgin female Wistar rats of six months old were divided into 6 groups: (1) rats in baseline group (base) were sacrificed what 6 months before OVX, and those in the other 5 groups were either bilaterally OVX or sham-operated (sham) as follows: (2) Sham; (3) OVX baseline (OVXb); (4) OVX end (OVXe); (5) OVX + 17beta-estradiol 20 microgram/kg.(-1) SC. (O + E); and (6) OVX + alfacalcidol 0.1 microgram/kg.(-1) oral (O + VD). Rats in OVXb group were sacrificed 6 weeks after OVX and the others were sacrificed 14 weeks after surgery. Alfacalcidol (TEVA, Israel) was fed orally at 6 weeks after OVX and lasted for 8 weeks. Urine and serum samples were collected before sacrifice to determine the bone turnover markers. The right tibia was processed undecalcified for histomorphometric analysis, and the right femur was prepared for pQCT scanning and bone biomechanical measurement with indentation test.

RESULTS

Treatment of OVX rats with alfacalcidol (O + VD) increased tibial cancellous bone volume in histomorphometric analysis (12.0% +/- 1.1% vs 5.8% +/- 1.3%, P < 0.01). pQCT scanning showed that trabecular BMC and BMD were sharply elevated in O + VD group compared with OVXe group, increased 109.2% and 133.1% respectively (P < 0.01). In consistency with these changes in mechanical competency of cancellous bone in distal femur, maximal load was enhanced in O + VD group compared with OVXe group (21.3% +/- 4.0% N vs 7.9% +/- 1.9% N, P < 0.05). All these changes in O + VD group were similar to those in 17beta-estradiol treatment group (O + E). Serum calcium concentration increased in O + VD group. Histomorphometric and biochemical indices of bone resorption reduced in O + VD group.

CONCLUSION

Alfacalcidol effectively prevent bone loss in OVX rats and restore partly the trabecula, with evidenced increasing density, contents as well as maximal loads of cancellous bone, and reduce bone resorption.

[Bone mineral analysis of whole body in 292 normal subjects assessed by dual X-ray absorptiometry]

OBJECTIVE

To understand whole body bone mineral changes in normal subjects.

METHODS

Bone mineral was measured by dual X-ray absorptiometry (DXA) in 292 normal subjects aged 10-79, including 152 females and 140 males. They were divided into age-groups by decade.

RESULTS

In males, peak value ages of total bone mineral content(TBMC), total bone mineral density(TBMD), anteroposterior spine BMD(L2-4 BMD) were in the 30-39, 20-39, 20-29 age-groups respectively. In females, they were all in the 30-39 age-group. Peak values of TBMC, TBMD, L2-4BMD were higher in males than those in females. Loss of bone mineral for females was more pronounced than that for males. There was a tendency of increased BMD among the 70-79 age-group for males. Loss of L2-4 BMD was more pronounced than TBMD.

CONCLUSIONS

This study provides the normal bone mineral data of whole body for males and females, and the characteristic of changes.

[Reconstruction of digital avulsion with pre-fabricated subdermal vascular network skin flap by ultrasonic liposuction]

OBJECTIVE

To investigate the clinical application of subdermal vascular network skin flap pre-fabricated by ultrasonic liposuction in reconstruction of digital avulsion.

METHODS

Forty-seven injured fingers of 23 cases were treated from June 1997 to February 2000. Conventional abdominal skin flap was elevated, according to the size of digital avulsion, and subcutaneous fat was removed with scissors. Ultrasonic liposuction technology was adopted, in order to minimize the injury of subdermal vascular vessels, to remove the fat particles close to the vascular network. Finally, the pre-fabricated skin flap was used to repair the digital avulsion. The vascular pedicle was severed in 5 to 7 days after operation. The range of skin flap was 4 cm x 3 cm to 8 cm x 7 cm, and the ratio of length and width was (2 to 3) to 1.

RESULTS

All the skin flaps were survived. Twenty-one patients were available for postoperative follow-up for 6 to 24 months. The motion of interphalangeal joint achieved functional recovery, and the sensation of pain, temperature and taction recovered well.

CONCLUSION

Ultrasonic liposuction does not obviously injure the subdermal vascular network skin flap, it is a simple and safe method for treatment of digital avulsion.

[Comparative study of the transplantation of vascular pedicle and traditional free tendon tissues]

The most frequent cause of failure after tendon transplantation is the formation of adhesions between the tendon graft and its surrounding tissues. In this study, the healing mechanism, adhesion formation and biomechanical properties of vascular pedicle and traditional free tendon grafts were compared in the rabbits. It was observed that the former remained normal histologically in healing process and had less adhesion formation; that of the latter underwent necrosis and was gradually replaced by new connective tissues, its adhesions were extensive and dense; and that the healing mechanism of the both tendon grafts at the anastomosed site were extrinsic, the biomechanical properties (rupture load and elastic stiffness) showed no statistically significant difference (P greater than 0.05). On the basis of these results, we believe that preserving of the blood supply of tendon graft is important for reducing the adhesion formation and improving the functional results.

[Normal spinal changes of bone mineral density in 445 individuals: assessment by quantitative computed tomography]

Spinal BMD was measured by QCT in 445 normal individuals aged 10-80 including 190 males and 255 females, which were divided into age-groups by every ten years. Statistic results showed that peak bone mass reached at 10-19 age-group for both male and female and that BMD assessed by QCT in females was not lower than that in males and BMD declined with increasing age. In females, BMD results in this study were different from those in USA. An acceleration bone loss was predominantly shown in the period after 40-49 age group. Among many factors related to bone loss, we consider that estrogen change may play a most important role for the remarkable bone loss in our country.

LDL oxidation by activated monocytes: characterization of the oxidized LDL and requirement for transition metal ions

Monocytes can be activated by incubation with opsonized zymosan (Zop), and under these conditions can oxidize low density lipoprotein (LDL). We have characterized the biochemical changes in the lipoprotein after this oxidation. We found that monocyte-oxidized LDL has increased mobility on agarose gels, increased absorbance at 234 nm, increased content of lysophosphatidylcholine, and fluorescence at 430 nm when excited at 350 nm. All these features were somewhat less pronounced in monocyte-oxidized LDL than in LDL oxidized by 5 micrometer CuSO4. Under appropriate conditions, Zop-stimulated monocytes oxidized LDL to a form recognized by macrophage scavenger receptors. Monocytes stimulated by Zop produced superoxide and also oxidized LDL, whereas monocytes stimulated by phorbol ester produced slightly more superoxide but did not oxidize LDL. We found that the chelators EDTA and diethylenetriaminepentaacetic acid inhibited LDL oxidation by Zop-stimulated monocytes, implying a requirement for transition metal ions. We found that Zop contained approximately 5 nmol iron per mg, probably as Fe3+. Zop stripped of its iron supported superoxide production by monocytes, but did not support LDL oxidation. Furthermore, Fe2+ appeared in the medium when monocytes were incubated with Zop, but not with iron-stripped Zop. Taken together, these results imply that monocytes stimulated by Zop are able to oxidize LDL only because of contaminating iron in the commercial zymosan preparations. and requirement for transition metal ions.

Influence of vibration on microdiameter measurements using a laser-charge-coupled device system

The influence of vibration on dynamic measurements of microdiameters using a laser diffraction-CCD detection system is studied. The theoretical analysis indicates that the influence of vibration on the diffraction pattern of a measured object introduces significant errors into its diameter measurement, and the improvement can be approached by using a TEM(00) Gaussian incident beam instead of the usual uniform beam. The experimental results of these cases are also presented and in good accordance with the theoretical analysis.

[Beta-diversity of Stipa communities in Inner Mongolia Plateau]

The beta-diversity characteristics of four Stipa communities (S. baicalensis, S. grandis, S. krylovii and S. klemenzii) were studied using comparable plots methods. As a measurement of species turnover within communities, Whittacker's index(beta ws) was size-dependent, and reduced gradually with the increasing quadrat size. Under the same scale, beta ws indices of the communities were similar. Cody's index (beta c) was also affected by sampling size. beta c increased initially as quadrat size enlarged, then stabilized over the size of 0.5 m2 for S. baicalensis and S. grandis communities, and 2 m2 for S. krylovii and S. klemenzii communities. S. baicalensis community had the highest Cody index, while S. klemenzii community had the lowest one. In most cases, the within-community distance interval had a relatively high effect on Cody index; From S. baicalensis to S. klemenzii community, the functional group diversities of forbs, perennial bunch and rhizome grasses decreased greatly, the diversity of intermediate xerads reduced significantly, and the diversity of xerads increased firstly, and then declined for S. klemenzii community. The changes in species composition of four Stipa communities could give a reflection to the degrees of community replacement along ecological gradients, and Cody indices between the communities reduced gradually. The Morisita-Horn similarity coefficient between S. baicalensis and S. grandis community was significantly higher (0.72) than those between S. grandis and S. krylovii communities (0.55), and between S. krylovii and S. klemenzii communities(0.42).

[The preliminary experiences of diagnosis and treatment for hypercalcemia crisis--clinical analysis of 23 cases]

This article report a study of 23 cases of hypercalcemia crisis resulting from primary hyperparathyroidism (18 cases), carcinoma (4 cases) and vitamin D intoxication (1 case). In addition to the symptoms of primary diseases, the patients with hypercalcemia crisis often had anorexia, nausea, vomiting, polydipsia, polyuria, psychoneurotic symptoms, arrhthmia. The severity of the symptoms was proportional to the degree of hypercalcimia. Serum calcium concentration of patients in hypercalcemia crisis should be equal or higher than 3.75 mmol/L (15 mg/dl) or serum ionized calcium higher than 1.88 mmol/L. Treatment hypercalcemia crisis consisted of rapidly lowering the serum calcium level by various measures while actively treating the primary diseases. Our experience is to supply normal saline intravenously or orally to increase the extracellular fluid and to enhance excretion of the urine calcium by administrating furosemide. In this paper, serum calcium concentration of 5 patients with hypercalcemia crisis treated with salmen calcitonin was reduced in varying degrees. The above mentioned treatment would be beneficial to the alleviation of the crisis and the preparation for operative treatment.

Scoping review on the role of social media in oral health promotion

OBJECTIVE

This review was conducted to assess the role of social media in oral health promotion by reviewing the perspectives and evaluation methods of previous related studies.

MATERIALS AND METHODS

The preferred reporting items PRISMA checklist was used to structure this review. Key search terms were identified to examine databases including PubMed, Web of Science and Embase. Manual searches in relevant journals and materials were also conducted in the meantime.

RESULTS

A total of 640 articles were identified after multi-source screening and duplicates removing, and finally 19 original studies published before April 2020 met the inclusion criteria. These studies mainly cover the fields of dentistry education and research, clinical treatment, and preventive dentistry. Both traditional and new-type social media have advantages and focuses, as well as biased information. Detailed assessment methods and indicators are classified into several groups, which could be selected to use in future research.

CONCLUSIONS

The application of social media in oral health promotion is becoming popular with the development of information technology. The broader use in the future, covering dentistry, mass health education, both long-term and short-term treatments of additional clinical content, requires further evaluation and supervision in online information sharing process. The reasonable selection of methods and indicators according to different topics and preference is of great importance.

P1689Nighttime blood pressure and dipping patterns relate to sodium sensitivity of blood pressure

Background

Attenuated nighttime blood pressure (BP) fall during a high-sodium diet is associated with higher sodium sensitivity of BP. However, the prognostic value for sodium sensitivity of nighttime BP profile during a habitual diet is not fully understood.

Purpose

To elucidate the usefulness of nighttime BP and dipping patterns under a habitual diet in assessing sodium sensitivity.

Methods

We conducted a dietary intervention study among 250 resident aged 18–60 years with high-normal or stage I hypertension in rural areas of northern China. The 24-hour ambulatory BP monitoring and baseline survey were performed for each participant under a habitual diet during the first 3 days. Then participants underwent a 7-day low-sodium intervention (51.3mmol sodium per day), followed by a 7-day high-sodium intervention (307.8mmol sodium per day). Three clinic BP measurements were obtained in every morning of the 3-day baseline observation and days 5, 6, and 7 of each intervention period.

Results

Among 250 participants, 86 (34.4%) had daytime hypertension (DH) and 149 (59.6%) had nighttime hypertension (NH). The systolic BP (SBP) responses to low-sodium and high-sodium intervention were significantly higher in those with NH than those without irrespective of DH status [−8.1 (−9.3, −7.0) vs. −5.5 (−7.0, −4.1) mmHg, P=0.001; and 13.0 (11.6, 14.3) vs. 11.0 (9.3, 12.7) mmHg, P=0.038, respectively]. Compared with dippers, extreme dippers had significantly higher SBP responses to low-sodium and high sodium intervention independently of 24-hour SBP. Moreover, the quadratic curve between nighttime SBP fall and SBP responses to low-sodium (β=−105.5 for quadratic term, P=0.015) and high-sodium (β=108.9 for quadratic term, P=0.035) intervention suggested both non-dipping and extreme dipping might indicate higher sodium sensitivity.

Conclusions

NH as well as non-dipping and extreme dipping determined during a habitual diet might indicate higher sodium sensitivity, which highlights the potential usefulness of nighttime BP profile in assessing sodium sensitivity.

Acknowledgement/Funding

This study is supported by the National Natural Science Foundation of China (grant no. 81570386)