Iron deficiency and risk factors in pre-menopausal females living in Auckland, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand
Background: Iron Deficiency (ID) is the most common nutrient deficiency worldwide,
affecting one third of the world’s population. In New Zealand (NZ), the highest rates
are found within pre-menopausal females, with previously identified risk factors for ID
including low meat intake, heavy menstruation and blood donation. Emerging risk
factors such as inflammation and obesity are yet to be explored in NZ, along with the
master hormone of iron regulation, hepcidin.
Objectives: To describe iron and hepcidin status within premenopausal females, and
identify risk factors for ID.
Methods: Females (n=170) aged 18–45 were recruited. Biomarkers of iron status
were measured: Serum ferritin (Sf), haemoglobin, soluble transferrin receptor,
hepcidin as well as inflammatory markers C-reactive protein and interluekin-6. Body
composition was measured using bioelectrical impedance analysis, and lifestyle
factors were assessed using questionnaires, including a previously validated food
frequency questionnaire. Variables known to potentially influence iron status were
entered into multiple linear regression analysis to identify predictors of Sf.
Results: Iron deficiency was confirmed in 55.8% of participants (Sf < 30µg·L-1).
Prevalence of ID did not differ significantly (p=0.141) between South Asians (64.3%),
NZ Europeans (51.6%), and those of other ethnicities (45.5%). Hepcidin
concentrations were higher in those who were iron sufficient (Sf ≥ 30µg·L-1) (6.62nM
vs 1.17nM, p<0.001). South Asian females had higher hepcidin (8.78nM)
concentrations, compared to NZ Europeans (6.28nM) and those of other ethnicities
(4.89nM) (p=0.026). The higher hepcidin concentrations in South Asian participants
are possibly associated with these participants having a higher BMI (p<0.001), body
fat percentage (p<0.001) and interlukein-6 (p<0.001) than NZ Europeans and other
ethnicities. Hepcidin (β=0.082, p<0.001) and frequency of meat intake (β=0.058,
p=0.001) were identified as significant predictors of Sf in NZ Europeans. Hepcidin was
the only identified predictor of Sf in South Asians (β=0.138, p<0.001) and those of
other ethnicities (β=0.117, p<0.002).
Conclusion: The study confirms a positive relationship between hepcidin and Sf in
NZ females, highlighting hepcidin’s potential as an emerging biomarker to identify ID.
Furthermore, there were differences in hepcidin levels between ethnicities, which may
be linked to higher levels of body fat and inflammation.