Haemoglobin concentrations appear to be lower in indigenous Greenlanders than in Danes: assessment of haemoglobin in 234 Greenlanders and in 2804 Danes

Determinants of iron deficiency and anemia among Nunavimmiut: results from the Qanuilirpitaa? 2017 Nunavik Health Survey

OBJECTIVE

To estimate the prevalence of iron deficiency (ID) and anemia and study their main distal and proximal protective and risk factors among Nunavimmiut 16 years and older in 2017.

METHODS

In a cross-sectional participatory survey of 831 women and 436 men from the Qanuilirpitaa? 2017 Nunavik Inuit Health Survey, venous blood samples were collected to measure various indicators of iron status and anemia as well as biomarkers of nutritional and inflammatory status and contaminant exposures. Sociodemographic, food security status, anthropometric, lifestyle, dietary, and health data were collected using questionnaires, clinical sessions, and a medical chart review. ID and anemia diagnoses were based on serum ferritin (SF) and hemoglobin (Hb), respectively. Multiple regressions were used to assess correlates of anemia and iron status.

RESULTS

Prevalence of ID was highest among women of childbearing age (16-49 years old, 33%) and anemia among adults aged 50 years and older (31%). These estimates are prone to biases due to the relatively low participation rate (37%). Serum vitamin D, omega-3 polyunsaturated fatty acid content of erythrocyte membranes, blood selenium, inflammation, higher socioeconomic status (SES), obesity, and alcohol consumption were all positively associated with SF, while Helicobacter pylori infection and a recent pregnancy were negatively associated with Hb among women of childbearing age. Among older adults, food insecurity was associated with lower SF.

CONCLUSION

While data reported here provide some indication of an improvement since the previous survey conducted in 2004, additional efforts should be devoted to further increasing the SES and access to country foods and nutritious market foods in this population, the two main protective factors against ID and anemia identified in the present study.

Impact of overweightness and critical weight loss on overall survival in patients with hepatocellular carcinoma initially treated with chemoembolization

BACKGROUND

The effects of overweightness and weight loss on the development and prognosis of hepatocellular carcinoma (HCC) remain unclear. In this study, we aimed to evaluate the impact of overweightness and weight loss on the survival of patients with intermediate/advanced HCC receiving chemoembolization as initial treatment.

METHODS

We examined 1,170 patients who underwent chemoembolization as initial treatment for Barcelona-Clínic Liver Cancer stages B and C HCC at Sun Yat-sen University Cancer Center (Guangzhou, China) between December 2009 and May 2015. A baseline body mass index (BMI) of ≥23 kg/m² was defined as overweight, and body-weight loss of ≥5.0% from baseline was defined as critical weight loss (CWL). Cox regression analysis was used to determine the association between overweightness or CWL and overall survival (OS).

RESULTS

The median survival time was 16.8 (95% confidence interval, 13.9-19.7) months and 11.1 (95% confidence interval, 10.0-12.2) months in the overweight and non-overweight groups (log-rank test, P < 0.001), respectively. Cox multivariate analysis identified overweightness as an independent protective prognostic factor for OS (P < 0.001). Subgroup stratification analysis revealed a significant association between overweightness and survival among patients receiving further treatment (P = 0.005), but not in those not receiving further treatment (P = 0.683). Multivariate analysis showed that both overweightness and CWL were independent prognostic factors for OS among patients receiving further treatment.

CONCLUSION

Among patients with intermediate- or advanced-stage HCC initially treated with chemoembolization, overweightness was associated with longer OS. Furthermore, CWL was an independent adverse prognostic factor for OS in patients receiving additional treatment.

Sero-prevalence of Helicobacter pylori CagA immunoglobulin G antibody, serum pepsinogens and haemoglobin levels in adults

Associations observed of Helicobacter pylori infection with haemoglobin levels are inconsistent. We examined associations of H. pylori sero-prevalence and serum pepsinogens (PGs), as non-invasive markers of atrophic gastritis, with haemoglobin levels. A cross-sectional study was undertaken among 654 Jewish and 937 Arab residents of Jerusalem, aged 25–78 years, randomly selected from Israel’s national population registry in age-sex and population strata. Sera were tested for H. pylori IgG, cytotoxin–associated gene A (CagA) antigen IgG antibody and PGs levels. Multivariable models were fitted to account for confounders. Participants with atrophic gastritis (PGI < 30 μg/L or a PGI: PGII < 3.0) had lower haemoglobin levels than those without: beta-coefficient −0.34 (95% CI −0.59, −0.09); in men −0.27 (95% CI −0.67, 0.12), and in women −0.43 (95% CI −0.74, −0.12). Lower haemoglobin levels were noted in persons with CagA antibody than in those H. pylori sero-negative or H. pylori-CagA sero-negative: beta-coefficient −0.14 (95% CI −0.29, 0.01). Anaemia was more common among women and men with than without atrophic gastritis: adjusted OR 2.58 (95% CI 1.48, 4.48) and 1.52 (95% CI 0.59, 3.95), respectively. In conclusion, independent of known correlates, atrophic gastritis and apparently CagA sero-positivity, a marker of H. pylori virulent strains, are associated with lower haemoglobin levels.

Changing reference intervals for haemoglobin in Denmark: Clinical and financial aspects

Introduction

Based on international experiences and altering demography the reference intervals (RI) for haemoglobin (Hb) concentrations in blood were changed in Denmark in 2013 from 113 - 161 g/L to 117 - 153 g/L for women and from 129 - 177 g/L to 134 - 170 g/L for men. The aim of this study was to determine the derived change in prevalence of anaemia and the change in yearly health care costs of diagnostic investigations associated with the expected, as we hypothesized, increased prevalence and health care costs.

Materials and methods

Data from 96,314 non-hospitalised patients (55,341 females and 40,973 males, aged 18 - 105 years) from general practitioners and community specialists of Funen, Denmark, were extracted from the laboratory information system. The prevalence of anaemia according to the new and the old RI were investigated, and additional costs were calculated based on estimated additional blood analyses and nationally recommended endoscopic procedures.

Results

Changing the Hb RI increased the number of anaemic patients by 52% (3450 patients) over a two-year period. With new RI the proportion of anaemic elderly above 80 years was 20.5% for females and 43.9% for males. Annual costs of derived additional assessments due to the altered RI were estimated to be 5.7 million €, which equals the cost of 1214 knee replacement surgeries in Denmark.

Conclusions

Changing the Hb RI has been expensive, despite the fact that no outcome studies have justified the alteration. The methodological approach for establishing new RI, here particularly for Hb, should be thoroughly considered. In general, physicians should use RI with caution.

Prevalence of unexplained anaemia in Inuit men and Inuit post-menopausal women in Northern Labrador: International Polar Year Inuit Health Survey

OBJECTIVE

To identify correlates of hemoglobin (Hb) and anaemia unexplained by iron deficiency (UA) in Canadian Inuit adults.

METHODS

A cross-sectional survey assessed diet, demographic information, anthropometry, fasting Hb, ferritin, soluble transferrin receptor (on a subset), high-sensitivity C-reactive protein (hs-CRP) in serum, red blood cell (RBC) fatty acid composition, blood lead, and antibodies to Helicobacter pylori in non-pregnant, Inuit adults (n = 2550), ≥18 years of age from randomly selected households in 36 Inuit communities in Inuvialuit Settlement Region, Nunavut Territory and Nunatsiavut of Northern Labrador, Canada.

RESULTS

Hb concentrations were lower and UA prevalence higher in Inuit men after 50 years of age. Rate of anaemia was constant among Inuit women but changed from primarily iron deficiency anaemia pre-menopause, to primarily UA in post-menopause. Low education levels and hs-CRP were associated with increased risk of UA. For Inuit men, % RBC eicosapentaenoic acid (EPA) and elevated blood lead were also associated with increased risk of UA. Frequency of traditional food intake was positively associated with Hb.

CONCLUSION

Age patterns and regional variation of anaemia suggest that ethnicity-related physiological differences cannot explain anaemia prevalence for Inuit. High RBC EPA status, inflammation and infections, and lower education levels may contribute to the prevalence of anaemia in this population, which is not related to iron status. Thus, traditional lifestyle may protect Inuit from nutritional anaemia but contribute to lower Hb through environmental exposures. The clinical significance of UA for older Inuit adults requires further investigation, as the prevalence represents a moderate public health problem.

Active and Passive Smoking and Serum Total Bilirubin in a Rural Korean Population

INTRODUCTION

Serum bilirubin is an endogenous antioxidant biomarker and its low level is a potential risk factor for smoking related health disorders. This study investigated the association of cigarette smoke with serum total bilirubin among Koreans.

METHODS

Between 2006 and 2011, we examined 4899 Korean adults living in a rural community. After excluding 38 participants with serum bilirubin more than 2mg/dL, 75 participants who did not report their smoking status or who had liver or bile duct disorders, and 711 participants with liver enzymes exceeding the upper reference values, we performed a cross-sectional analysis on 4075 participants. Participants were classified into four groups: never-smokers without secondhand smoke exposure (SHSE), never-smokers with SHSE, former smokers, and active smokers. Serum total bilirubin concentration was measured using the enzyme method.

RESULTS

Compared to never-smokers without SHSE, never-smokers with SHSE (β = -0.025 mg/dL), former smokers (β = -0.049 mg/dL), and active smokers (β = -0.149 mg/dL) had significantly lower serum bilirubin even after adjusting for demographic factors, study year, alanine aminotransferase, gamma-glutamyl transferase, hemoglobin, lifestyle factors, and chronic diseases. A sex-stratified analysis indicated that for men, former smokers and active smokers were significantly associated with having lower bilirubin when compared to never-smokers without SHSE. However, for women, never-smokers with SHSE and active smokers were significantly associated with having lower bilirubin when compared to never-smokers without SHSE.

CONCLUSION

Our findings suggest that both active and passive cigarette smoking are associated with low serum bilirubin among Korean adults.

IMPLICATIONS

Our results suggest that not only active smoking but also passive smoking including SHSE can have an influence on decreasing serum bilirubin levels. With this different point of view, our study supports efforts to create smoke-free environments in order to foster more favorable serum bilirubin profiles, which may improve endothelial function and reduce the risk of cardiovascular disease.

Combined effects of smoking and bilirubin levels on the risk of lung cancer in Korea: the severance cohort study

BACKGROUND

Smoking is a major risk factor for lung cancer. Bilirubin, an antioxidant, is inversely associated with the risk of diseases related to oxidative stress. This study was conducted to determine the influence of smoking and bilirubin levels on the risk of lung cancer in the Severance cohort study.

METHODS

This study included 68,676 Korean who received a health examination at Severance Health Promotion Center from 1994 to 2004. Serum bilirubin measurements within normal range were divided into tertiles whereas smoking states were divided as never-smokers, former smokers and current smokers. A diagnosis of lung cancer was coded as occurring based on the report from the National Cancer Registry. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated using Cox proportional hazards model.

RESULTS

At the end of the study period, 240 patients (men: 181, women: 59) developed lung cancer. Compared to those with bilirubin levels ≥ 1.0 mg/dL, HRs (95% CI) for lung cancer were 2.8 (1.8-4.2) for subjects having bilirubin levels from 0.2 to 0.7 mg/dL in men. When we stratified our analysis by smoking status, bilirubin consistently showed a protective effect on the risk of lung cancer on both never- and current smokers. Current smokers having bilirubin levels from 0.2 to 0.7 mg/dL had a risk of lung cancer by 6.0-fold higher than never-smokers with bilirubin levels ≥ 1.0 mg/dL in men.

CONCLUSION

In this large prospective study, higher baseline bilirubin level in the normal range was associated with low risk of lung cancer. Smoking and low bilirubin levels were cumulatively associated with a higher risk of lung cancer.

Population groups in dietary transition

Background

Little is known about the effects of dietary acculturation in minority groups in the Nordic countries, including immigrants from non-Western societies.

Methods

A search was performed in Medlin33e/PubMed and SweMed+ for articles published in 1990–2011.

Results

A total of 840 articles were identified, with a final 32 articles used to tabulate results which were included in the primary analysis. High rates of vitamin D deficiency (23 articles) were found in immigrants of non-Western origin; deficiency rates were very high among both pregnant and non-pregnant women, and also among children, with young children of immigrant parents showing 50 times higher risk for rickets when compared to children of indigenous parents. The risk of iron deficiency (two articles) was high among immigrant women, while the results were inconclusive regarding children. High rates of dental caries (seven articles) were found among pre-school and younger school children of immigrant origin, while the risk of caries was not as evident among older children. In a secondary analysis, including 48 articles (results not tabulated), overweight and obesity (14 articles) were seen in many immigrant groups, resulting in a high prevalence of diabetes (2 review articles from a total of 14 original articles) and incidence of coronary heart disease (CHD; seven articles). For hypertension (three articles), dyslipidemia (four articles), and dietary patterns among immigrants (10 articles), the results were contradictory.

Conclusions

Risk of vitamin D deficiency is alarmingly high in the Nordic countries among immigrants of non-Western origin, especially among women. Dental caries is high among immigrant children aged 0–7 years due to a higher intake of sugary products. Overweight and obesity, associated with a higher risk of diabetes and CHD, are prevalent in many immigrant groups and need further attention.

Higher n3-fatty acid status is associated with lower risk of iron depletion among food insecure Canadian Inuit women

BACKGROUND

High rates of iron deficiency and anemia are common among Inuit and Arctic women despite a traditional diet based on animal source foods. However, representative data on iron status and relevant determinants for this population are lacking. The objectives were to determine the prevalence of anemia and depletion of iron stores, then to identify correlates of iron status in non-pregnant Canadian Inuit women.

METHODS

In a cross-sectional survey of 1550 women in the International Polar Year Inuit Health Survey, 2007-2008, hemoglobin, serum ferritin, soluble transferrin receptor (on a subset), C-reactive protein (CRP), RBC fatty acid composition, and H pylori serology were analyzed on fasting venous blood. Sociodemographic, food security status, anthropometric, dietary, and health data were collected. Correlates of iron status were assessed with multivariate linear and logistic models.

RESULTS

Anemia was observed in 21.7% and iron deficient erythropoiesis in 3.3% of women. For women with CRP ≤ 10 mg/L (n = 1260) 29.4% had depleted iron stores. Inadequate iron intakes were observed in 16% of premenopausal and <1% of postmenopausal women. Among food insecure women, higher long-chain (n-3) polyunsaturated fatty acid (LC-PUFA) status, which reflects a more traditional food pattern, was associated with reduced risk of iron depletion.

CONCLUSIONS

Iron depletion and anemia are a concern for Inuit women despite adequate total dietary iron intake primarily from heme sources. The high prevalence of H. pylori exposure, together with dietary iron adequacy, suggests an inflammation-driven iron deficiency and mild anemia. The anti-inflammatory properties of LC-PUFA may be important for iron status in this population.

Traditional food intake is correlated with iron stores in Canadian Inuit men

Accelerated loss of traditional lifestyles may place Inuit at risk of iron depletion given that anemia has been observed among Arctic men. The objectives of this study were to determine the prevalence of anemia, storage iron depletion, and iron overload and to identify correlates of iron status in Canadian Inuit men. In a cross-sectional survey of 994 men in the International Polar Year Inuit Health Survey, 2007-2008, hemoglobin, serum ferritin (SF), soluble transferrin receptor (on a subset), CRP, RBC fatty acid composition, and Helicobacter pylori serology were measured in venous blood drawn from fasting men. Anthropometric, dietary, sociodemographic, and health data were collected. Dietary and nondietary correlates of iron status were assessed with multiple linear and logistic models. For men with CRP ≤10 mg/L (n = 804), 6.5% had depleted, 19.8% had low, and 10.3% had elevated iron stores. Anemia was moderately prevalent (16.1%), but iron deficiency anemia was less common (2.4%). There was a low probability of dietary iron inadequacy (2.4% < Estimated Average Requirement) and excess iron intakes (10.7% > Tolerable Upper Intake Level). Food-insecure men and those without a household hunter had a higher risk of low or depleted iron stores. Adiposity, traditional food intake, long-chain RBC PUFA status, and inflammation were positively associated with SF and food insecurity, smoking, and H. pylori seropositivity were negatively associated with SF. Despite a moderate prevalence of anemia, iron stores are largely adequate in this population, although lower than expected based on iron intake. The regulation of iron metabolism in this population and the high prevalence of anemia in older men warrants further investigation.

Cigarette smoking and serum bilirubin subtypes in healthy Korean men: the Korea Medical Institute study

OBJECTIVES

Cigarette smoking is a modifiable risk factor for cardiovascular disease. Bilirubin is a potent antioxidant and its concentration decreases in smokers. However, studies about the association between cigarette smoking and bilirubin are scarce and most are limited to total bilirubin. Additionally, bilirubin is highly related to hemoglobin. Therefore, this study evaluates the association between bilirubin subtypes and cigarette smoking in healthy Korean men independently of hemoglobin.

METHODS

This study included 48 040 Korean men aged 30 to 87 years who visited the Korea Medical Institute for routine health examinations from January to December, 2007. The association of smoking with total, direct, and indirect bilirubin was assessed by logistic regression analysis taking into consideration differences in subjects and smoking characteristics.

RESULTS

Current smokers had lower bilirubin concentrations than never-smokers and ex-smokers. Smoking amount and duration were inversely significantly associated with total, direct, and indirect bilirubin. In a multivariable adjusted model, compared to never-smokers, the odds ratios (ORs) and 95% confidence intervals (CIs) of current smokers with the highest number of pack-years were 1.7 (1.6 to 1.9) for total, 1.5 (1.4 to 1.6) for direct, and 1.7 (1.6 to 1.9) for indirect bilirubin. After further adjustment for hemoglobin, this association became stronger (OR [95% CI], 2.1 [1.9 to 2.2] for total; 1.9 [1.8 to 2.0] for direct; 2.0 [1.9 to 2.2] for indirect bilirubin).

CONCLUSIONS

In this study, bilirubin subtypes are inversely associated with smoking status, smoking amount, and smoking duration in healthy Korean men independently of hemoglobin. Further studies are needed to investigate this association in healthy Korean women.

Changes in body mass index and smoking habits have a different impact on hemoglobin concentration in men and women: a longitudinal follow-up of the Tromsø Study, 1994-2002

BACKGROUND

Body mass index (BMI) and smoking have been positively associated with hemoglobin concentration, and both are risk factors for cardiovascular disease.

OBJECTIVE

The aim of this study was to assess whether there were sex differences in how changes in BMI and smoking habits influenced hemoglobin concentration.

METHODS

In 1994-95 and 2001-02, a longitudinal, population-based study was conducted in the municipality of Tromsø, in northern Norway. Inhabitants aged > or =25 years were invited to participate. Participants replied to a questionnaire regarding health, physical activity, coffee and alcohol consumption, and smoking habits. Blood samples were drawn to analyze hemoglobin concentration. All analyses were performed separately for each sex. Differences between 1994-95 and 2001-02 were examined with t or chi(2) (McNemar) tests for paired data. Cross-sectional comparisons were made using 2-sample t tests. Different models of univariate and multiple linear regression analyses were used to investigate the impact of the various variables on hemoglobin change.

RESULTS

Data from a total of 2105 men and 2945 women were examined. At baseline, mean age was 58.9 years for men (range, 25-78 years) and 57.8 years for women (range, 25-82 years); mean BMI was 26.1 kg/m(2) for men and 25.8 kg/m(2) for women. In men, hemoglobin decreased with age, on average from 147.5 to 145.1 g/L. In women, hemoglobin decreased from 135.6 to 134.7 g/L, but increased with increasing age up to 54 years, and thereafter decreased gradually. Mean BMI increased 0.8 kg/m(2) in men and 1.2 kg/m(2) in women. In total, 394 of 2057 men (19%) and 499 of 2889 women (17%) stopped smoking or smoked fewer cigarettes per day. In a univariate regression model, an increase of 1 kg/m(2) in BMI was associated with an increase in hemoglobin of 1.1 g/L (95% CI, 0.84 to 1.27) in men and 0.4 g/L (95% CI, 0.30 to 0.56) in women. In another univariate model, smoking cessation was associated with a decrease in hemoglobin of 1.9 g/L (95% CI, -3.32 to -0.56) in men and 1.7 g/L (95% CI, -2.93 to -0.56) in women. In men who smoked less and had a BMI increase of >2.5 kg/m(2), hemoglobin decreased 0.3 g/L. In contrast, hemoglobin decreased 3.4 g/L in men who smoked less and lost weight (P for trend, < 0.001 by changing BMI). Women who smoked less had a decrease in hemoglobin independent of BMI changes.

CONCLUSIONS

The positive association between an increase in BMI and hemoglobin was stronger in men than in women. The effect of smoking reduction on hemoglobin was attenuated with increasing BMI in men, but not in women.

Prevalence, incidence and types of mild anemia in the elderly: the "Health and Anemia" population-based study

BACKGROUND

Hemoglobin concentrations slightly below the lower limit of normal are a common laboratory finding in the elderly, but scant evidence is available on the actual occurrence of mild anemia despite its potential effect on health. The objectives of this study were to estimate the prevalence and incidence of mild grade anemia and to assess the frequency of anemia types in the elderly.

DESIGN AND METHODS

This was a prospective, population-based study in all residents 65 years or older in Biella, Italy.

RESULTS

Blood test results were available for analysis from 8,744 elderly. Hemoglobin concentration decreased and mild anemia increased steadily with increasing age. Mild anemia (defined as a hemoglobin concentration of 10.0-11.9 g/dL in women and 10.0-12.9 g/dL in men) affected 11.8% of the elderly included in the analysis, while the estimated prevalence in the entire population was 11.1%. Before hemoglobin determination, most mildly anemic individuals perceived themselves as non-anemic. Chronic disease anemia, thalassemia trait, and renal insufficiency were the most frequent types of mild anemia. The underlying cause of mild anemia remained unexplained in 26.4% of the cases, almost one third of which might be accounted for by myelodysplastic syndromes. In a random sample of non-anemic elderly at baseline (n=529), after about 2 years, the annual incidence rate of mild anemia was 22.5 per 1000 person-years and increased with increasing age.

CONCLUSIONS

The prevalence and incidence of mild anemia increase with age and mild anemia affects more than one out of ten elderly individuals. Unexplained anemia is common and may be due to myelodysplastic syndromes in some cases.

Hemoglobin concentrations in 358 apparently healthy 80-year-old Danish men and women. Should the reference interval be adjusted for age?

BACKGROUND AND AIMS

In elderly Danes, reference intervals for hemoglobin (Hb) concentrations are derived from younger population groups. The aim was to examine reference intervals for Hb and cut-off limits for anemia by application of criteria for normality to a representative population of 80-year-olds.

METHODS

Participants in this epidemiological health survey cohort were 358 subjects (171 men) 80 years of age. A dietary survey was performed in 232 subjects. Blood samples included Hb, red cell indices, serum ferritin, serum C-reactive protein, renal and hepatic function tests. Normality criteria for Hb were: 1) values in all participants; 2) values in apparently healthy subjects; 3) values in 10-year survivors. Hb was compared with muscle strength, physical performance and diet.

RESULTS

In the entire series, median Hb was 140 g/L, 5-95 percentile 116-160 g/L in men, and 131 g/L, 5-95 percentile 114-147 g/L in women (p<0.001). The prevalence of anemia, as defined by World Health Organization (WHO) criteria, was 18% in men and 17% in women. Apparently healthy iron-replete men (n=129) and women (n=141) had median Hb of 141 g/L and 131 g/L. Median Hb levels were higher in 10-year surviving men (143 g/L) than in deceased men (139 g/L), whereas surviving and deceased women had similar median Hb (131 g/L). Hb and muscle strength were significantly correlated. Subjects with physical performance score >or=20 had a lower frequency of anemia. There was no correlation between Hb and dietary or supplemental iron intake. In men, Hb was correlated to meat consumption.

CONCLUSIONS

WHO decision limits for anemia should not be lowered in 80-year-old subjects. "Optimal" Hb concentrations with respect to survival appear to be at least 140 g/L in men and 131 g/L in women. Further research should evaluate whether not only treating anemia, but also increasing Hb by using erythropoietin and hematinics, may improve functional status and survival in the elderly.

Robust, routine haematology reference ranges for healthy adults

Accurate, reliable laboratory reference ranges are essential for effective clinical evaluation and monitoring. We present robust reference ranges established for haematology, coagulation and haematinic parameters using the Sysmex XE 2100, CA 1500 and Beckman-Coulter Access analysers. Blood samples were taken from 250 healthy laboratory personnel and routine haematology, coagulation and haematinic parameter analysis performed. Our data represent findings from an extensive study to establish reference ranges in healthy adults.

Nutritional iron deficiency: an evolutionary perspective

Iron deficiency, with or without iron-deficiency anemia, is so ubiquitous that it affects all populations of the world irrespective of race, culture, or ethnic background. Despite all the latest advances in modern medicine, improved nutrition, and the ready availability of cheap oral iron, there is still no good explanation for the widespread persistence of iron deficiency. It is possible that the iron deficiency phenotype is very prevalent because of many factors other than the commonly cited causes such as a decreased availability or an increased utilization of iron. Several thousand years ago, human culture changed profoundly with the agrarian revolution, when humans turned to agriculture. Their diet became iron deficient and new epidemic infections emerged due to crowding and lifestyle changes. There is convincing evidence that iron deficiency protects against many infectious diseases such as malaria, plague, and tuberculosis as shown by diverse medical, historical, and anthropologic studies. Thus, this change of diet increased the frequency of iron deficiency, and epidemic infections exerted a selection pressure under which the iron deficiency phenotype survived better. Multiple evolutionary factors have contributed in making iron deficiency a successful phenotype. We analyze some of the recent findings of iron metabolism, the theories explaining excessive menstruation in human primates, the unexplained relative paucity of hemochromatosis genes, the former medical practice of "blood-letting," and other relevant historical data to fully understand the phenomenon of iron deficiency. We suggest that, due to a long evolutionary persistence of iron deficiency, efforts at its prevention will take a long time to be effective.

Changes in haemoglobin levels according to changes in body mass index and smoking habits, a 20-year follow-up of a male cohort

Haemoglobin level declines with increasing age in cross sectional studies. Little is known about the longitudinal changes of haemoglobin. Because both high or low haemoglobin levels increase mortality and morbidity we examined how changes in lifestyle factors like body mass index (BMI) and smoking habits influence cohort changes in haemoglobin level. In all, 4159 men aged 20-49 years at baseline were examined in 1974 and 1994-1995 in a longitudinal, population-based study from the municipality of Tromsø, Northern Norway. Mean haemoglobin was 148 g/l. There was no difference in mean haemoglobin after 20 years in any strata of age. Mean BMI increased 2.1 kg/m(2). The prevalence of smokers decreased 20.1 percentage points. In a multiple regression analysis increase in BMI was associated with increased haemoglobin change. Smoking cessation lowered mean haemoglobin 1.6 g/l compared to never smokers. Haemoglobin increased 0.8 g/l in smoking quitters whose BMI increased >2.5 kg/m(2) compared to a decrease of 6.7 g/l in weight reducers. There was a positive dose-response relationship between changes in cigarettes smoked per day and change in haemoglobin among consistent smokers. In conclusion, in contrast to cross sectional studies, mean haemoglobin did not change during 20 years ageing of relatively young men. This could be explained by higher BMI and less smoking. The increase in BMI affected haemoglobin change to such an extent that the reduction in haemoglobin due to smoking cessation was counteracted. Prospective studies are needed to address the health implications.

Haemoglobin and anaemia in a gender perspective: the Tromsø Study

OBJECTIVES

To examine the gender-specific distribution of haemoglobin (Hb) and the World Health Organization (WHO) criteria for anaemia compared with the 2.5 percentile for Hb.

METHODS

A population-based study from Tromsø, Northern Norway. All inhabitants above 24 yr were invited. In total, 26 530 (75%) had their Hb analysed.

RESULTS

The 2.5-97.5 percentile of Hb was 129-166 and 114-152 g/L for all men and women, respectively. In men, mean Hb decreased from 148 to 137 g/L between 55-64 and 85+ yr. In women, mean Hb increased from 132 to 137 g/L between 35-44 and 65-74 yr and then decreased to 131 g/L among the oldest. Using the WHO criteria for anaemia (Hb: <130 and <120 g/L, men and women respectively), the prevalence of anaemia in men increased with age from 0.6% aged 25-34 to 29.6% aged 85+. For women, the prevalence of anaemia varied from 9.1%, 2.2% and 16.5% in the age groups of 35-44, 55-64 and 85+ yr, respectively. The WHO criteria gave a two to three times higher prevalence of anaemia compared with the 2.5 percentile of Hb in women, but the difference was small in men. Poor self-rated health was not associated with low values of Hb in women. In men, there was an association in some age groups.

CONCLUSION

The WHO criteria for anaemia and the 2.5 percentile for Hb corresponded well for men, but not for women. The WHO criteria of anaemia may result in medicalization of healthy women.

Issues to debate on the Women's Health Initiative: estrogen: an instrument or the conductor of the orchestra?

Although it is well known that cyclic production of sex hormones is essential to establish reproductive function and female characteristics, distant impacts of the activity of the female endocrine system result from a concert of delicate mechanisms. Estrogen is rather an instrument than a conductor in this physiological orchestra of the female. Thus, controversies in the explanation of results from studies on hormone replacement therapy (HRT) and cardiovascular disease (CVD) prevention might be eliminated, if we analyse not only the role of estrogen but a broader spectrum of factors leading to CVD. Authors would like to hypothesize that haemorheological changes in women around menopause, such as increased blood and plasma viscosity, haematocrit and fibrinogen, are largely responsible for the increased mortality in the post-menopausal life period. We believe that a cyclic withdrawal bleeding establishes a more favourable haemorheological condition, thus, sequentially administered estrogen might be protective in post-menopausal women. Nevertheless, other factors, that decrease blood viscosity, such as daily exercise, intake of ample amount of fluids as well as ideal nutrition, are equally important. We are confident that sequential HRT, as well as healthy life style and risk prevention programmes have their proper place in the management of this issue.

The quantitative assessment of body iron

Current initiatives to reduce the high prevalence of nutritional iron deficiency have highlighted the need for reliable epidemiologic methods to assess iron status. The present report describes a method for estimating body iron based on the ratio of the serum transferrin receptor to serum ferritin. Analysis showed a single normal distribution of body iron stores in US men aged 20 to 65 years (mean +/- 1 SD, 9.82 +/- 2.82 mg/kg). A single normal distribution was also observed in pregnant Jamaican women (mean +/- 1 SD, 0.09 +/- 4.48 mg/kg). Distribution analysis in US women aged 20 to 45 years indicated 2 populations; 93% of women had body iron stores averaging 5.5 +/- 3.35 mg/kg (mean +/- 1 SD), whereas the remaining 7% of women had a mean tissue iron deficit of 3.87 +/- 3.23 mg/kg. Calculations of body iron in trials of iron supplementation in Jamaica and iron fortification in Vietnam demonstrated that the method can be used to calculate absorption of the added iron. Quantitative estimates of body iron greatly enhance the evaluation of iron status and the sensitivity of iron intervention trials in populations in which inflammation is uncommon or has been excluded by laboratory screening. The method is useful clinically for monitoring iron status in those who are highly susceptible to iron deficiency.

Longitudinal trends of hemoglobin levels in a Japanese population--RERF's Adult Health Study subjects

Conflicting results have been reported on the long-term relationship between hemoglobin (Hb) level and age. We analyzed that relationship over a 40-yr period in a Japanese population, adjusting for the effects of sex, birth cohort, smoking, and anemia-associated diseases. We used Hb levels measured biennially between 1958 and 1998 for 4858 Adult Health Study subjects of the Radiation Effects Research Foundation. Using the mixed-effects model, we showed that the aging Hb profile varied by sex (P < 0.001) and birth cohort (P < 0.001). Male Hb levels peaked in the third and fourth decades and then decreased while female Hb levels dipped slightly in the third decade, peaked in the sixth and seventh, and then decreased. Levels were higher in younger cohorts. The rate of Hb decline after the sixth decade of life was greater for subjects with anemia-associated diseases (P = 0.002). The annual rate of decline between 70 and 80 yr of age for disease-free men ranged from 0.083 to 0.042 g/dL and for disease-free women from 0.049 to 0.036 g/dL. Levels were higher for ever-smokers (P < 0.001), more so for women than men. A decreasing trend in Hb concentration with advancing age was detected for elderly men and women after controlling for anemia-associated diseases, suggesting that anemia in the elderly is due not only to disease but also to aging. Cohort and smoking effects on Hb levels were also observed.

Iron status markers in 224 indigenous Greenlanders: influence of age, residence and traditional foods

OBJECTIVE

To evaluate iron status in indigenous Greenlanders and its relationship to gender, age and intake of traditional Greenlandic foods.

METHODS

Serum ferritin, serum transferrin saturation and haemoglobin were evaluated in a population survey in 1993-1994 comprising 224 Greenlandic individuals (109 men) aged 19-82 yr. The participants were residents in the capital Nuuk (n=73) with a predominantly Western style of living, the town Ilulissat (n=60) with a mixture of Western and Greenlandic style of living, and the small town Uummannaq (n=91) with a predominantly Greenlandic style of living. Consumption of traditional foods was assessed by questionnaire.

RESULTS

Intake of traditional foods was more prevalent among elderly than among young individuals and more frequent in Uummannaq than in Ilulissat and Nuuk. Ferritin levels were higher in men than in women (p<0.0001). Median ferritin levels were lowest in Nuuk (men, 92 microg/L; women, 40 microg/L), higher in Ilulissat (men, 104 microg/L; women, 69 microg/L) and in Uummannaq (men, 118 microg/L; women, 46 microg/L) (p<0.001). The prevalence of iron load (ferritin >200 microg/L) was lowest in Nuuk (men: 13.8%, women: 2.3%) intermediate in Ilulissat (men, 11.1%; women, 9.1%) and highest in Uummannaq (men, 32.1%; women, 21.1%). The prevalence of iron depletion (ferritin <16 microg/L) was high in Nuuk (men, 0%; women, 20.5%), and lower in Ilulissat (men, 3.7%; women, 6.1%) and in Uummannaq (men, 0%; women, 10.5%). The prevalence of iron deficiency anaemia (ferritin <13 microg/L and Hb <5th percentile for iron-replete men and women) was 0.92% in men and 0.87% in women. Correlations between age and ferritin were lowest in Nuuk (men, r(s)=0.26, p=0.2; women, r(s)=0.50, p=0.001) intermediary in Ilulissat (men, r(s)=0.37, p=0.06; women, r(s)=0.73, p<0.0001) and highest in Uummannaq (men, r(s)=0.59, p<0.0001; women, rs=0.74, p<0.0001). Intake of traditional foods was correlated with ferritin in men (r(s)=0.29, p=0.01) and women (r(s)=0.40, p<0.0001).

CONCLUSION

The observed differences in estimated body iron stores in Greenlanders from the three residential areas can be explained by differences in the dietary intake of haem iron.