Klinisk Biokemi i Norden · 3 2015
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of conditions and diseases. Although this activity has
greatly enhanced our knowledge of the metabolism
of fatty acids, there is still a long way to go before
we fully understand their influence and action in
human physiology.
The thesis
In my thesis, I review current knowledge of essential
fatty acids in relation to health effects, physiological
actions and molecular mechanisms. The original
investigations were performed in two separate popu-
lations. The first two papers use fatty acids measu-
rements performed in patients with newly diagnosed
type 2 diabetes recruited from the Nord-Trøndelag
Health (HUNT) Study, Norway, and their matched
controls. The third paper is based on measurements
in elderly patients acutely admitted to St Olavs hos-
pital in Trondheim, Norway.
In
paper I
[1], we report long term tracking of
plasma phospholipid fatty acid concentrations and
their correlation with the dietary intake of marine
foods in newly diagnosed diabetic patients. The
study provides data for 29 plasma phospholipid
(PL) FA concentrations and indices measured in 214
newly diagnosed type 2 diabetic patients at baseline
and after 3 years. In measurements 3 years apart,
tracking coefficients (Spearman’s r) for docosahexa-
enoic acid (DHA), eicosapentaenoic acid (EPA) and
PLN3-index (EPA + DHA) were 0.60, 0.47 and 0.55,
respectively. Fish consumption measured simulta-
neously with EPA, DHA, sum n-3 and PLN3 index
showed Spearman’s correlation coefficients of 0.47,
0.44, 0.48 and 0.49, respectively, decreasing to 0.20,
0.19, 0.22 and 0.21 when measured 3
years apart. The within-subject CV
of EPA, DHA and PLN3 index were
39.9, 14.3 and 18.0 %, respectively.
The corresponding between-subject
CV were 33.6, 16.5 and 18.7 %, while the
reference change values were 112, 41 and 52 %. We
conclude that PL n-3 FA concentrations showed a sig-
nificant long-term tracking and were positively cor-
related with marine food intake. Analytical precision,
biological variability, reference change value and the
index of individuality of EPA, DHA and PLN3 index
are similar to commonly used clinical biomarkers,
supporting their validity as dietary markers in clini-
cal and epidemiological work.
In
paper II
[2], we investigated the association
between plasma phospholipid fatty acid relative
concentrations expressed as weight percentage and
total mortality in patients with type 2 diabetes.
Mortality rates were evaluated at 5, 10, 15 and 20
years in patients with newly diagnosed diabetes (n=
323) and matched non-diabetic controls (n= 200).
Kaplan–Meier survival curves were constructed
and Cox regression analysis was used to calculate
hazard ratios (HR) adjusted for biochemical and
clinical covariates. After 10 years of follow-up, EPA
in the diabetic population was negatively associated
with total mortality, with an HR at the fifth quintile
of 0.47 (95 % CI 0.25, 0.90) compared with the first
quintile. In contrast, DHA was positively associated
with total mortality, with an HR at the fifth quintile
of 2.87 (95 % CI 1.45, 5.66). Neither EPA nor DHA
was associated with total mortality in matched non-
Omega-
6
Omega-3
Omega-6
Omega-3
