. Author manuscript; available in PMC: 2019 Oct 28.

Published in final edited form as: Br J Nutr. 2019 Aug 28;122(4):376–387. doi: 10.1017/S0007114519001430

Table 2.

Characteristics of four case–control studies on the association between blood calcium concentrations and incidence of diabetes

Source	Participants (n)	Age (years)	Males (%)	Exposure assessment	Cases		Controls		Case identification methods	Adjusted variables
Source	Participants (n)	Age (years)	Males (%)	Exposure assessment	n	Blood Ca	n	Blood Ca	Case identification methods	Adjusted variables
Heath et al.⁽³⁴⁾, USA	122	Untreated, 58 (se 1) Treated A^*, 43 (se 5); Treated B^†, 51 (se 4); Control 44 (se 2)	53·3	Fasting serum total Ca	Total, 82, Untreated, 47 Treated A^*, 19 Treated B^†, 16	Untreated, 9·4 (se 0·1) mg/dl Treated A^*, 9·2 (se 0·1) mg/dl Treated B^†, 9·4 (se 0·1) mg/dl	40	9·4 (se 0·1) mg/dl	All were judged by endocrinologist	-
				Fasting serum ionised Ca	7	Untreated, 4·22 (se 0·6) mg/dl	11	4·2 (se 0·1) mg/dl
McNair et al.⁽³⁵⁾, Denmark	48	Case, 28·5 (range 16–41); Control, 25·7 (range 16–40)	Case, 47·8; Control, 64·0	Fasting pH-adjusted serum ionic Ca	25 insulin-treated DM	1·16 (se 0·01) mmol/l	23	1·20 (se 0·01) mmol/l	-	-
Levy et al.⁽¹⁸⁾, Israel	184	Case, 48 (sd 4); Control 48 (sd 4)^‡	Case, 52·2; Control, 52·2^‡	Fasting plasma Ca	92	2·48 (se 0·004) mmol/l	92^‡	2·38 (se 0·006) mmol/l	-	Age, sex and mode of treatment
Sorva & Tilvis⁽⁷⁾, Finland	504	80 (sd 9)	Case, 28·8; Control, 19·0	Fasting serum total/ionised Ca concentrations	125	CaT, 2·31 mmol/lCal, 1·24 mmol/l	379	CaT, 2·27 mmol/l Cal, 1·23 mmol/l	Use antidiabetic medication or fasting plasma glucose exceeded 7 mmol/l	Albumin

DM, diabetes mellitus; CaT, total Ca; Cal, ionised, actual Ca.

Treated A: fasting plasma glucose > 200 mg/dl.

^†

Treated B: fasting plasma glucose < 200 mg/dl.

^‡

Matched with the case group.