Bone mineral density in primary care patients related to serum calcium concentrations: a longitudinal cohort study from Sweden

Figures & data

Figure 1. Flow chart of study subjects, including drop-outs, with elevated and normal calcium concentrations at base line at Tibro Health Care Centre, Sweden: first investigation in 1995–2000, and re-examination in 2009–2010.

Table 1. Characteristics of patients with elevated and normal calcium concentrations at baseline, 1995–2000 and 2008–2010, men and women, at Tibro Health Care Centre, Sweden.

	Patients with baseline elevated calcium concentrations						Patients with baseline normal calcium concentrations						Comparison between groups
VariablesData at baseline	Total		Men		Women		Total		Men		Women		Total	Men	Women
1995–2000	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	p value	p value	p value
Number	127		28		99		254		56		198
Age, January 1st 1995	61.4	17.5	55.6	17.6	63.0	17.1	61.3	17.5	55.5	17.7	62.9	17.1	n.s.	n.s.	n.s.
Age, range	18–94		18–82		18–94		18–91		18–82		18–91
	Median	Percentile	Median	Percentile	Median	Percentile	Median	Percentile	Median	Percentile	Median	Percentile
Calcium^a	2.60	2.56–2.78	2.65	2.57–2.88	2.60	2.56–2.78	2.34	2.21–2.43	2.32	2.19–2.42	2.35	2.21–2.44	<0.001	<0.001	<0.001
Data at follow-up
2009–2010	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD
Number	57		11		46		118		30		88
Age, January 1st 2011	70.6	14.8	66.8	12.5	71.5	15.5	68.3	15.6	65.3	14.7	69.2	15.8	n.s.	n.s.	n.s.
Age, range	31–94		45–82		31–94		30–97		31–85		30–97
≥80 years old	19		3		16		32		5		27		n.s.	n.s.	n.s.
Body height	164	153–177	176	170–182	161	151–169	164	153–177	176	169–184	161	152–171	n.s.	n.s.	n.s.
Body weight	73.1	55.4–93.4	87.5	74.0–100.0	69.5	54.7–89.4	74.4	57.0–94.2	82.8	65.8–101.4	71.7	55.9–92.0	n.s.	n.s.	n.s.
BMI	27.1	21.2–32.8	28.1	25.9–32.7	26.9	21.1–32.8	27.6	21.7–34.2	26.8	22.2–32.2	27.8	21.6–34.9	n.s.	n.s.	n.s.
	Median	Percentile	Median	Percentile	Median	Percentile	Median	Percentile	Median	Percentile	Median	Percentile
Calcium^b	2.45	2.27–2.58	2.45	2.28–2.51	2.44	2.27–2.59	2.34	2.25–2.47	2.33	2.24–2.42	2.35	2.25–2.48	<0.001	0.019	<0.001
Ionised Calcium^c	1.28	1.22–1.38	1.28	1.26–1.30	1.28	1.22–1.40	1.23	1.18–1.27	1.23	1.20–1.26	1.23	1.18–1.27	<0.001	<0.001	<0.001
Parathyroid hormone^d	53	21–103	39	20–92	54	21–103	46	26–104	44	24–95	46	29–110	n.s.	n.s.	n.s.
ALP^e	1.20	0.85–1.60	1.20	0.90–1.60	1.20	0.84–1.60	1.20	0.80–1.70	1.10	0.88–1.40	1.25	0.80–1.71	n.s.	n.s.	n.s.

Percentile, 10th and 90th percentile. Data are means (SD), n.s. = not significant, Age in years. Height in centimetres. Weight in kilogrammes. BMI (Body Mass Index) in kilogrammes/metre². Reference range ^aSerum Calcium analysed in whole blood (mmol/L) 2.15–2.55, ^bPlasma Calcium (mmol/L) 2.15–2.50, ^cSerum Ionised Calcium (mmol/L) 1.15–1.35, ^dSerum Parathyroid hormone (ng/L) 15–65, ^ePlasma ALP: Alkaline phosphatase (µkat/l) 0.6–1.8.

Table 2. Clinical characteristics and bone mineral variables, 2009–2010, in patients with elevated and normal calcium concentrations at baseline, 1995–2000 and 2008–2010, men and women, at Tibro Health Care Centre, Sweden.

	Patients with baseline elevated calcium concentrations						Patients with baseline normal calcium concentrations						Comparison between groups
	Total		Men		Women		Total		Men		Women		Total	Men	Women
Number of participants	57		11		46		118		30		88		n.s.	n.s.	n.s.
Questionnaire
Previous fragility fracture	16		2		14		31		7		24		n.s.	n.s.	n.s.
Reduction by ≥5 cm in height^a	10		2		8		27		3		24		n.s.	n.s.	n.s.
Smokers (current or past)	17		5		12		37		10		27		n.s.	n.s.	n.s.
>9 standard drinks alcohol per week	3		3		0		3		3		0		n.s.	n.s.	n.s.
Medication
Bisphosphonates + calcium & vitamin D	6		0		6		5		0		5		n.s.	n.s.	n.s.
Calcium & vitamin D	4		0		4		12		0		12		n.s.	n.s.	n.s.
Corticosteroids ≥5 mg ≥3 months	9		0		9		4		1		3		0.013	n.s.	0.010
Clinical investigation
BMI <20 kg/m^2	4		1		3		4		1		3		n.s.	n.s.	n.s.
Diagnosis after investigation
Primary hyperparathyroidism	26		5		21		2		0		2		<0.001	<0.003	<0.001
Parathyroidectomy	13		2		11		0		0		0		<0.001	n.s.	<0.006
Bone density	mean	SD	mean	SD	mean	SD	mean	SD	mean	SD	mean	SD
Left radius (g/cm^2)	0.62	0.15	0.77	0.11	0.58	0.13	0.61	0.13	0.74	0.12	0.60	0.13	n.s.	n.s.	n.s.
T-score	−1.88	1.77	−0.82	1.15	−1.93	1.76	−1.53	1.53	−1.00	1.36	−1.70	1.54	n.s.	n.s.	n.s.
Lumbar spine L2-L4 (g/cm^2)	1.09	0.20	1.26	0.16	1.06	0.18	1.09	0.20	1.22	0.17	1.09	0.19	n.s.	n.s.	n.s.
T-score	−1.12	1.56	−0.03	1.22	−1.36	1.54	−0.78	1.59	−0.01	1.45	−0.99	1.58	n.s.	n.s.	n.s.
Right femur neck (g/cm^2)	0.79	0.19	0.96	0.21	0.84	0.17	0.84	0.14	1.00	0.11	0.86	0.14	n.s.	n.s.	n.s.
T-score	−1.38	1.48	−1.26	1.56	−1.41	1.45	−1.15	1.06	−0.71	0.86	−1.21	1.09	n.s.	n.s.	n.s.
Left femur neck (g/cm^2)	0.77	0.21	0.99	0.22	0.83	0.20	0.86	0.14	1.00	0.13	0.88	0.13	n.s.	n.s.	n.s.
T-score	−1.23	1.41	−1.02	1.58	−1.28	1.35	−1.03	1.06	−0.73	1.01	−1.12	1.06	n.s.	n.s.	n.s.
Number of vertebral fracture assessment	50		10		40		111		27		84		n.s.	n.s.	n.s.
Vertebral compression fracture	9		1		8		17		2		15		n.s.	n.s.	n.s.

Notes: Previous fragility fracture (distal forearm, vertebra, humerus, and proximal femur), ^aAnamnestically. BMI: body mass index.

Figure 2. Patients with elevated and normal calcium concentrations divided at baseline into three groups, depending on the results of the absorptiometry: normal bone density ≥ −1 SD, osteopaenia: < −1.0 SD and > −2.5 SD, osteoporosis: ≤ −2.5 SD. Re-examination in 2009–2010 of patients from Tibro Health Care Centre, Sweden. Panel A. All patients. Panel B. Patients divided by gender.

Endres DB. Investigation of hypercalcemia. Clin Biochem. 2012;45:954–963.

 PubMed Web of Science ®Google Scholar

Nordenstrom E, Katzman P, Bergenfelz A. Biochemical diagnosis of primary hyperparathyroidism: Analysis of the sensitivity of total and ionized calcium in combination with PTH. Clin Biochem. 2011;44:849–852.

 PubMed Web of Science ®Google Scholar

Dalemo S, Hjerpe P, Ohlsson H, et al. Variation in plasma calcium analysis in primary care in Sweden – a multilevel analysis. BMC Fam Pract. 2010;11:43.

 PubMed Web of Science ®Google Scholar

Lindstedt G, Nystrom E, Lundberg PA, et al. Screening of an elderly population in primary care for primary hyperparathyroidism. Scand J Prim Health Care. 1992;10:192–197.

 PubMedGoogle Scholar

Applewhite MK, Schneider DF. Mild primary hyperparathyroidism: a literature review. Oncologist. 2014;19:919–929.

 PubMed Web of Science ®Google Scholar