Læknablaðið - 15.02.1998, Page 8

96
LÆKNABLAÐIÐ 1998; 84
Hámarksbeinmagn íslenskra kvenna
Áhrif íþrótta og næringarþátta
Gunnar Sigurðsson1-21, Örnólfur Valdimarsson, 2), Jón Örvar Kristinsson1'21, Sigurjón Stefánsson31,
Sindri Valdimarsson3*, Heiða B. Knútsdóttir3’, Þórhalla Andrésdóttir31, Leifur Franzson14|, Laufey
Steingrímsdóttir51
Sigurðsson G, Valdimarsson Ö, Kristinsson JÖ,
Stefánsson S, Valdimarsson S, Knútsdóttir HI5,
Andrésdóttir Þ, Franzson L, Steingrímsdóttir L
Peak bone mass of Icelandic women and associat-
ed factors
Læknablaðið 1998; 84: 96-105
Objective: The aim of this study was to evaluate at
which age peak bone mass is reached among
Icelandic women. Previous studies on this subject
have been conflicting indicating that this might be
reached sometime between the age of 16 and 35
years. We have also analyzed associated nutritional
and physical factors which might be of use for pre-
ventive measures against osteoporosis.
Material and methods: Arandom sample of 16, 18,
20 and 25 years old women in Reykjavík were invit-
ed, altogether 335 women participated. Bone miner-
al density (BMD) was analyzed by Dual Energy X-
ray Absorptiometry (DEXA) in the lumbar spine,
hip, forearm and total skeleton. Calcium, protein and
vitamin D intake was assessed by a semiquantitative
food frequency questionnaire. The level of 25-OH-
vitamin D in serum was measured by a radioim-
munoassay. Physical activity was assessed by a ques-
tionnaire. Multivariate analysis was performed by
multiple linear regression.
Results: Maximal bone mineral density was reached
for total skeleton, hip and forearm at the age of 20
years, BMD for the lumbar spine was 1% higher at
Frá ''rannsóknarstofa Sjúkrahúss Reykjavíkur um bein-
brot og beinþynningu, 2llyflækningadeild SHR, 3,lækna-
deild Háskóla íslands, '"rannsóknardeild SHR,5lManneldis-
ráði íslands. Fyrirspurnir, bréfaskipti: Gunnar Sigurðsson,
lyflækningadeild Sjúkrahúss Reykjavíkur Fossvogi, 108
Reykjavík.
Lykilorð: hámarksbeinmagn, vítamín-D, kalkneysla,
Hkamshreyfing, íþróttir.
the age of 25 than at 20 years but this was not statis-
tically significant. No significant association was
found between the calcium intake and BMD except
in the subgroup of 18 years old women with calcium
intake below 1000 mg/day. 25-OH-vitamin D levels
were low (<25 nmol/L) in 15-18.5% of the groups
but still no significant relationship was found with
the bone mineral density. The strongest correlation
was found between total BMD and the lean mass
(0.38-0.53, p<0.01) but physical activity was also a
significant factor in the age groups 16-20 years.
About 25-30% of BMD variability can be attributed
to these modifiable factors.
Conclusion: Peak bone mass seems to be reached at
the age of 20 and measures to increase it should
therefore be emphasized before that age. Our results
indicate that modifiable factors, especially lean mass
and physical activity, are of considerable importance
in the attainment of peak bone mass in women.
Key words: peakbone mass, lcelandic women, exercise,
vitamin-D intake, calcium intake.
Ágrip
Tilgangur: Tilgangur þessarar rannsóknar
var að kanna hvenær hámarksbeinmagni er náð
meðal íslenskra kvenna og hvaða þættir séu því
tengdir. Slík vitneskja skiptir máli ef unnt er að
auka hámarksbeinmagnið með til dæmis
lífsvenjum eða mataræði.
Efniviður og aðferðir: Beinmagn í slembi-
hópi íslenskra kvenna, 16, 18, 20 og 25 ára
(alls 335) var mælt með DEXA tækni og borið
saman við vissa næringarþætti, svo sem kalk,
prótín og D-vítamín svo og ltkamshreyfingu
(metið með stöðluðum spumingalistum). Magn
fitu og mjúkvefja (lean mass) mælt með DEXA
var einnig borið saman við beinmagnið.