Anderson Nr

Ethnic differences in total and HDL cholesterol concentrations: Caucasians compared with predominantly Punjabi Sikh Indo-Asians

Background In comparison with Caucasians, Indo-Asians resident in the UK have similar total cholesterol but lower HDL cholesterol (HDLC) concentrations. It is however possible that cardiovascular risk factors may vary between culturally different Indo-Asians. Methods We present data on 223 Indo-Asians (129 men, 94 women) and 787 Caucasians (421 men, 366 women) in whom a laboratory-based coronary heart disease (CHD) risk score calculation had been requested. Results Total cholesterol concentrations were similar in Indo-Asians and Caucasians. HDLC concentrations were higher (P< 0·001) in Caucasians [1·4 (1·3–1·4) mmol/L; median (95% confidence intervals)] than in Indo-Asians [1·2 (1·2–1·3) mmol/L]. Indo-Asian women [1·2 (1·2–1·3) mmol/L], Indo-Asian men [1·2 (1·2–1·3) mmol/L] and Caucasian men [1·2 (1·2–1·3) mmol/L] had similar HDLC concentrations but these were all lower (P< 0·001) than those in Caucasian women [1·4 (1·3–1·4) mmol/L]. Conclusion We confirm low HDLC concentrations in Indo-Asians, but propose that this is solely due to low HDLC concentrations in Indo-Asian women. Since Indo-Asians in Wolverhampton are predominantly Punjabi Sikhs, we suggest that the difference between this study and previous reports may be due to heterogeneity of CHD risk factors within culturally diverse Indo-Asians.

Ethnic Variation in C-Reactive Protein: UK Resident Indo-Asians Compared with Caucasians

Background The increased prevalence of coronary heart disease (CHD) in UK resident Indo-Asians is unexplained by the traditional cardiovascular risk factors of dyslipidaemia, hypertension, smoking and diabetes mellitus. C-reactive protein (CRP) has been implicated in the pathogenesis of CHD but the data on ethnic variation in CRP is conflicting. We therefore investigated whether CRP could help explain the increased prevalence of CHD in Indo-Asians. Design and methods We measured CRP, using a highly sensitive assay, in 102 men (63 Caucasians and 39 Indo-Asians) and 89 women (58 Caucasians and 31 Indo-Asians). All subjects, aged between 40 and 70 years, were nondiabetic and nonsmokers. Results Serum CRP correlated (P < 0.05) positively with coronary risk. Serum HDL cholesterol concentrations were lower (P<0.05) in Indo-Asian women when compared with Caucasian women, but otherwise the ethnic groups were matched for calculated coronary risk and cardiovascular risk factors. Serum CRP concentrations were similar in Indo-Asians (women 2.29 (1.52) mg/l {mean (SD)}; men 1.77 (1.46) mg/l) and Caucasians (women 2.23 (1.54) mg/l; men 1.94 (1.45) mg/l). Conclusions Altered CRP concentrations does not appear to be implicated in the increased prevalence of CHD in UK resident Indo-Asians.

Effect of a protease inhibitor on in vitro stability of intact parathyroid hormone

Background: We investigated whether increased protease activity explains the increased in vitro degradation of intact parathyroid hormone (iPTH) observed in serum when compared to EDTA plasma. Methods: Pre-dialysis blood samples for iPTH were taken from 11 patients with chronic renal failure and collected into plain glass tubes, tubes containing 200 KIU/mL aprotinin (a protease inhibitor) and EDTA tubes. All sample aliquots were separated at 20 min, 1 h, 2 h, 4 h, 8 h and 24 h post collection. Results: Over 24 h, iPTH concentrations remained unchanged in EDTA tubes. iPTH concentrations were significantly lower in both plain tubes (P < 0·01) and aprotinin tubes (P < 0·001) at 24 h when compared to the baseline sample (20 min). At 24 h, iPTH concentrations in EDTA tubes were higher than in plain tubes (P < 0·001) and aprotinin tubes (P < 0·01). The addition of aprotinin to plain tubes significantly reduced the degradation of iPTH (P < 0·05) at 24 h. Conclusion: Aprotinin significantly reduces the in vitro degradation of iPTH in plain tubes at 24 h from 24·7% to 9·6%. We suggest that increased protease activity contributes to the decline in serum iPTH over time. As this is observed in serum and not plasma it suggests that the increased protease activity may be due to the clotting process.

Lipaemia: an overrated interference?

Abstract Reagent method sheets for analysis of common serum analytes often highlight the possibility of interference from lipaemia but the information given is often brief and may not be instrument-specific. Thus study assesses the degree of interference from lipaemia in a range of common serum analytes on the Bayer Opera (with a serum blank) using a commercial polymer, LipoClear, as a lipid-clearing agent. Serum samples (mean serum triglyceride 6.89 [range 0.58–28.4] mmol/L) are analysed for 14 common chemistry analytes and the results compared before and after treatment with LipoClear. Results showed no significant critical differences in analyte values before and after treatment, except for an expected fall in total protein, phosphate, cholesterol and triglyceride concentrations. Most of the common analytes in use on the Bayer Opera are not subject to interference from lipaemia; however, we recommend that where method sheets indicate interference from lipaemia then this should be quantified for the analyte in question.

Pseudo-pseudohypercalcaemia, apparent primary hyperparathyroidism and Waldenström's macroglobulinaemia.

An apparent primary hyperparathyroidism was reported due to pseudo-pseudohypercalcaemia in a 74–year-old man with Waldenström’s macroglobulinaemia. It is important to recognise artificially elevated serum calcium levels so as to avoid erroneous diagnosis, unnecessary investigations and potentially inappropriate treatment.

Effect of sample tube type and time to separation on in vitro levels of C-reactive protein.

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