Blackwood A M, Sagnella G A, Cook D G, Cappuccio F P
Department of Medicine, St George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, UK.
J Hum Hypertens. 2001 Apr;15(4):229-37. doi: 10.1038/sj.jhh.1001171.
Hypertension is associated with increased urinary calcium excretion (UCa). A high sodium intake increases both UCa and blood pressure (BP). However, it is not clear whether these effects are modified by gender or ethnic origin.
To examine the relationships between BP, urinary sodium (UNa), gender and ethnic origin with both daily and fasting UCa in a population-based study.
Out of 1577 individuals taking part in a cross-sectional survey, 743 were considered for the present analysis (407 women, 336 men) as they were all untreated, had provided a complete 24-h urine collection, and had all measurements of anthropometry, BP, UNa and UCa. They were 277 whites, 227 of black African origin and 239 South Asians. Comparisons were also carried out in the 690 participants who also provided 3-h fasting urine collections.
After adjustment for confounders including age, and gender, 24-h UCa was significantly and independently associated with ethnic origin, BP and UNa. Mean 24-h UCa was 4.62 (s.e. 0.11) mmol/d in whites, 3.33 (0.12) in South Asians and 3.16 (0.13) in blacks (P < 0.001). a 100 mmol higher UNa predicted a 1.04 mmol higher daily UCa (P < 0.001), and a 20 mm Hg higher systolic BP predicted a 0.28 mmol higher UCa. The slopes were not significantly different by ethnic group. The ethnic differences in UCa were present when fasting UCa was used instead (1.64 [0.05] micromol/min in whites, 1.08 [0.06] in South Asians and 1.13 [0.06] in blacks; P < 0.001).
These results indicate that BP, salt intake and ethnic origin are independent predictors of UCa in an unselected population. These relationships are unlikely to be the result of differences in Ca intake or intestinal Ca absorption as they are seen also after an overnight fast, suggesting that they may reflect differences in renal tubular handling. The estimated effects of either BP or sodium intake on UCa, sustained over many years, may be associated with significant effects on bone calcium content.
高血压与尿钙排泄量（UCa）增加有关。高钠摄入会增加尿钙排泄量和血压（BP）。然而，尚不清楚这些影响是否会因性别或种族而有所不同。
在一项基于人群的研究中，探讨血压、尿钠（UNa）、性别和种族与每日及空腹尿钙排泄量之间的关系。
在参与横断面调查的1577名个体中，743名（407名女性，336名男性）被纳入本分析，因为他们均未接受治疗，提供了完整的24小时尿液收集，且进行了人体测量、血压、尿钠和尿钙的所有测量。其中有277名白人、227名非洲黑人后裔和239名南亚人。对另外690名也提供了3小时空腹尿液收集的参与者也进行了比较。
在对包括年龄和性别在内的混杂因素进行调整后，24小时尿钙排泄量与种族、血压和尿钠显著且独立相关。白人的平均24小时尿钙排泄量为4.62（标准误0.11）mmol/d，南亚人为3.33（0.12）mmol/d，黑人为3.16（0.13）mmol/d（P<0.001）。尿钠每升高100 mmol，预测每日尿钙排泄量升高1.04 mmol（P<0.001），收缩压每升高20 mmHg，预测尿钙排泄量升高0.28 mmol。不同种族的斜率无显著差异。改用空腹尿钙排泄量时，尿钙的种族差异依然存在（白人1.64[0.05]微摩尔/分钟，南亚人1.08[0.06]微摩尔/分钟，黑人1.13[0.06]微摩尔/分钟；P<0.001）。
这些结果表明，在未经过选择的人群中，血压、盐摄入量和种族是尿钙排泄量的独立预测因素。这些关系不太可能是钙摄入量或肠道钙吸收差异的结果，因为在禁食过夜后也观察到了这些关系，这表明它们可能反映了肾小管处理的差异。血压或钠摄入量对尿钙排泄量的估计影响持续多年，可能会对骨钙含量产生显著影响。
