Andreas S. Rigas

Predictors of iron levels in 14,737 Danish blood donors: results from the Danish Blood Donor Study

Dietary studies show a relationship between the intake of iron enhancers and inhibitors and iron stores in the general population. However, the impact of dietary factors on the iron stores of blood donors, whose iron status is affected by blood donations, is incompletely understood.

Combined Oral Contraception and Obesity Are Strong Predictors of Low-Grade Inflammation in Healthy Individuals: Results from the Danish Blood Donor Study (DBDS)

Background C-reactive protein (CRP) is a well-established marker of inflammation. The level of CRP is affected by several lifestyle factors. A slightly increased CRP level, also known as low-grade inflammation (LGI), is associated with increased risk of several diseases, especially cardiovascular disease. The aim of this study was to identify predictors of increased CRP levels in healthy individuals. We therefore assessed CRP in a large cohort of blood donors. Methods We measured plasma CRP levels in 15,684 participants from the Danish Blood Donor Study. CRP was measured by a commercial assay. Furthermore, all participants completed a standard questionnaire on smoking status, alcohol consumption, physical activity, diet, and various body measurements. Female participants also reported the use of contraception, childbirth, and menopausal status. The relationship between LGI (defined here as a plasma CRP level between 3 mg/L and 10 mg/L) and predictors was explored by multivariable logistic regression analysis. Results were presented as odds ratios (OR) with 95% confidence intervals (CI). Results We found LGI in a total of 1,561 (10.0%) participants. LGI was more frequent in women using combined oral contraception (OC) (29.9%) than in men (6.1%) and women not using OC (7.9%). Among premenopausal women, OC was the strongest predictor of LGI (odds ratio = 8.98, p<0.001). Additionally, body mass index (BMI) and waist circumference were positively associated with LGI. Conclusion High BMI and abdominal obesity strongly predicted LGI among healthy individuals. However, the most striking finding was the high prevalence of LGI among premenopausal women who used combined oral contraception. Although the significance of CRP as a marker of inflammation is well known, the role of CRP in pathogenesis is still uncertain. The impact of oral contraception on CRP levels should nevertheless be considered when CRP is used in risk assessment.

No association between iron status and self-reported health-related quality of life in 16,375 Danish blood donors: results from the Danish Blood Donor Study.

Health‐related quality of life (HRQL) represents peoples subjective assessment of their mental and physical well‐being. HRQL is highly predictive of future health. The effect of iron deficiency without anemia induced by blood donation on HRQL is presently unknown. The aim was to explore the relationship between iron status and self‐reported mental component score (MCS; SF‐12) and physical component score (PCS; SF‐12) in Danish blood donors.

Predictors of hemoglobin in Danish blood donors: results from the Danish Blood Donor Study.

It is well known that blood donors are at increased risk of iron deficiency and subsequent development of iron deficiency anemia. We aimed to investigate the effect of factors influencing hemoglobin (Hb) levels.

Prevalence of restless legs syndrome and associated factors in an otherwise healthy population: results from the Danish Blood Donor Study

OBJECTIVE Restless legs syndrome (RLS) is a neurological sensorimotor disorder characterized by uncomfortable sensations in the legs. RLS often occurs as a comorbid condition. Besides an increased risk of iron deficiency, blood donors are considered to be generally healthy. Blood donors are therefore an ideal population for studying factors associated with RLS occurrence, herein the role of iron. It is suggested that RLS is linked to sex, age, low socioeconomic status, unhealthy lifestyle, and iron deficiency. The objective of this study is therefore to estimate the RLS prevalence and identify associated biological, sociodemographic, economic, and lifestyle factors in a population of blood donors. METHODS A total of 13,448 blood donors enrolled in the Danish Blood Donor Study from May 2015 to May 2016. RLS cases were identified using the validated Cambridge-Hopkins RLS-questionnaire. Logistic regression models were applied to assess the relationship between RLS and data on socially related factors collected using questionnaires and population registers. RESULTS In this study, 7.2% women and 4.5% men were classified with RLS. RLS was associated with: female sex, high age, smoking, frequent alcohol consumption, and low education. RLS-related symptoms were associated with obesity, parity and donation intensity three years prior to inclusion among women. RLS was not related to: reduced plasma ferritin, employment status, and income. CONCLUSIONS RLS is a frequent disorder in otherwise healthy individuals. The associations discovered in this study can be utilized in preventing or reducing RLS symptoms.

Genetic factors influencing ferritin levels in 14,126 blood donors: results from the Danish Blood Donor Study

Many biologic functions depend on sufficient iron levels, and iron deficiency is especially common among blood donors. Genetic variants associated with iron levels have been identified, but the impact of genetic variation on iron levels among blood donors remains unclear.

Low-grade inflammation is associated with lower haemoglobin levels in healthy individuals: results from the Danish blood donor study

Chronic inflammation can lead to anaemia of chronic disease due to the sequestration of iron caused by inflammatory cytokines and the protein hepcidin. However, the effect of low‐grade inflammation (LGI) on haemoglobin among healthy individuals is not known. This study examines the effect of LGI on haemoglobin among Danish blood donors.

Restless legs syndrome is associated with major comorbidities in a population of Danish blood donors

BACKGROUND Restless Legs Syndrome (RLS) is characterized by uncomfortable nocturnal sensations in the legs making sedentary activities and sleep difficult, and is thus linked with psychosocial distress. Due to the symptomatology and neurobiology of RLS (disrupting brain iron and dopamine) it is likely that RLS associates with poorer health-related quality of life (HRQL) and depressive disorder. The objective of this study was to investigate the RLS-HRQL and the RLS-depressive disorder links in a generally healthy population that is not biased by medications. METHODS Complete data, including the Cambridge-Hopkins RLS questionnaire, the 12-item short-form standardized health survey (SF-12), the Major Depression Inventory (MDI), body mass index, smoking status, alcohol consumption, and education were available for 24,707 participants enrolled in the Danish Blood Donor Study from May 1, 2015 to February 1, 2017. Information on quality of sleep was available for all RLS cases. T-tests and multivariable logistic regression models were applied to examine the associations of RLS and MDI scores, and the physical and mental component scores (PCS and MCS) of SF-12, respectively. Analyses were conducted separately for men and women. RESULTS RLS associated with poorer MCS and poorer PCS. Moreover, Participants with RLS were more likely to classify with depressive disorder. Poor quality of sleep was associated with depressive disorder and poorer MCS among RLS cases, and with poorer PCS in female RLS cases. CONCLUSION Thus, we demonstrated that RLS is associated with a significantly lower HRQL and a higher prevalence of depressive disorder among otherwise healthy individuals.

Iron deficiency among blood donors: experience from the Danish Blood Donor Study and from the Copenhagen ferritin monitoring scheme: Iron deficiency among blood donors

Blood components collected from blood donors are an invaluable part of modern‐day medicine. A healthy blood donor population is therefore of paramount importance. The results from the Danish Blood Donor Study (DBDS) indicate that gender, number of previous donations, time since last donation and menopausal status are the strongest predictors of iron deficiency. Only little information on the health effects of iron deficiency in blood donors exits. Possibly, after a standard full blood donation, a temporarily reduced physical performance for women is observed. However, iron deficiency among blood donors is not reflected in a reduced self‐perceived mental and physical health.

Deferral for low hemoglobin is not associated with increased risk of infection in Danish blood donors

Low hemoglobin (Hb) is associated with poor general health and adverse outcomes in a wide range of diseases. However, a link between Hb levels and the risk of infection among healthy individuals has yet to be investigated.