Feasibility of Dual-Energy X-ray Absorptiometry in Arctic field studies

BACKGROUND

Bone strength decreases with age. Bone mineral density (BMD) is a measure of bone strength. Data on BMD in present-day Inuit are limited, and data on circumpolar populations using Dual Energy X-ray Absorptiometry (DEXA scanning) are lacking.

OBJECTIVES

Our aims were to validate DEXA scanning for use in field studies in the Arctic region and to obtain data on BMD in Greenland Inuit.

METHODS

We measured BMD in 52 healthy Inuit living in Ilulissat and Saqqaq in North Greenland using a portable peripheral DEXA scanner. The measurement sites were forearms and calcaneal bones. Two measurements were performed at both radii and both calcanei. Triplicate measurements were performed in eleven Inuit.

RESULTS

The portable scanner fitted into a standard bag suitable for transportation in the arctic winter. Imprecision was well within 2% for all calibrations. CV% were 0.16% to 1.79% in the forearms and 0.38% to 1.53% in the heels. The overall CV% was 1.09% in forearm and 1.01% in heel. Mean BMD in men was 0.569 g/cm2 in forearms and 0.542 in heel. In women it was 0.479 in forearms and 0.468 in heel.

CONCLUSION

DEXA scanning is a feasible, reliable and comfortable method in rural Greenland. BMD values are now available for Greenland Inuit.

Ethnic differences in bone mineral density between inuit and Caucasians in north Greenland are caused by differences in body size

Data on bone mineral density (BMD) in living Inuit are limited and BMD measurements in Arctic Inuit using Dualenergy X-ray Absorptiometry (DXA) are lacking. Ethnicity may be important for bone mass. The aim of this study was to validate DXA in rural Arctic Greenland, to measure BMD in Greenland Inuit and Caucasians, and to estimate the importance of ethnicity for BMD. We measured the BMD in 80 healthy subjects living in Ilulissat and Saqqaq in North Greenland twice in both distal forearms and in both heels using peripheral DXA (pDXA). Participants were stratified by origin (Inuit[settlement])/Caucasians, n = 33 [19]/28), gender (men/women, n = 37/43), and age (30-39/40-49, n = 32/48). Caucasians were bigger than Inuit (men/women, height p < 0.001/p < 0.001; weight p = 0.01/ p = 0.026), but had similar BMI (p = 0.42/0.70). Triplicate pDXA measurements showed individual CV% = 0.16-1.79%; overall CV% = 1.1% (forearm)/1.0% (heel). Data followed the normal distribution (p = 0.65-0.99) with identical variances between Inuit and Caucasians (p = 0.12-0.63). Mean BMD in right forearm/left forearm/right heel/left heel was: Inuit men 0.570/0.568/0.549/0.536 g/cm2; Inuit women 0.484/0.474/0.473/0.464 g/cm2; Caucasian men 0.580/0.570/0.646/0.638 g/cm2; Caucasian women 0.495/0.496/0.552/0.553 g/cm2. An ethnic difference in heel BMD (p < 0.001) disappeared when adjusted for weight (p = 0.30). No difference was found in forearm BMD. In conclusion, pDXA is feasible and reliable in rural Greenland. Ethnic differences in BMD are small and may reflect differences in body size.