The haematological profile of four hundred (400) apparently health adult Nigerian residing in Zaria, aged 60-85years old were studied and compared with young adults control 20-30 years in order to establish haematological reference values for the aged men and women. Haematocrit, haemoglobin, red blood cell counts, white blood cell counts, differential white blood cell counts, platelet counts, mean cell volume, means cell haemoglobin and mean cell Haemoglobin concentration were analyzed using cell Haematology analyzer (CELL Dyn 4000) and erythrocyte sedimentation rate (ESR) was determined using westergreen method. The mean value of RBC count, Hb, Hct, WBC count, Platelet count and neutrophils were significantly lower in apparently healthy elderly male and female (P<0.001) than in control. All hematological parameters estimated showed sex and age related differences except basophils and MCHC. ESR showed sex and age differences with higher mean value in apparently healthy elderly females. A slight decrease in the mean values of neutrophils was observed in both sexes and ages. Mean value of MCV, MCH, lymphocytes, eosinophils and monocytes were significantly increased in the elderly males and females compared to those in the young adult control (P<0.001). Based on physiological variation (age and sex) the reference value for fourteen (14) haematological constituents of blood have been estimated, in order to provide medically reliable evaluation of haematological values in the elderly males and females. The use of seperates reference haematological values for the aged adults is hereby advocated; further study to ascertain the actual causes of low haemalogical value in the elderly is hereby recommended.
Key Words: Haematological parameter, Geriatrics, Zaria.
Ageing is a general physiology process which affects cell and the systems made up of them, as well as tissue components.
In old age red bone marrow sites are slowly replaced with yellow inactive marrow. Red marrow forms all types of blood cells and it is also one of the largest and most active organs of the human body.
It may be tempting to assume that blood counts may be low in the elderly because of the established fatty changes in the marrow with age (1).
No markers of alternatives of erythrocytes physiology and production clearly to ageing have been stated, nor even is it clear if Laboratory haematological values need to be adjusted to the age (2). Anaemia is observed to be common in the elderly and its prevalence increase with age. However anaemia should not be accepted as an inevitable consequence of ageing. Most elderly persons are able to maintain their haemoglobin level above anaemia level and secondly up to 80% of anaemic elderly people have an identifiable causes of anaemia when investigated (3). The normal haematopoiesis constitutes the process of producing diverse, differentiated blood cell types in a manner related to physiological requirement.
During ageing, modulation of haematopoiesis becomes disordered, impairing the ability of older people to respond appropriately to the demand for the blood cell replacement triggered by stimuli such as blood loss or cytoreductive chemotherapy (3).
In addition, age-related event such as genomic secondly to oxidative stress and impaired regulation of cytokine production, may contribute to or cause the emergence of abnormal clones of haematopoietic cells referred to as myelodysplastic syndromes (4).
Studies of haematological ageing in humans generally begin with investigation of population samples representative for the background population regarding age, sex, health status, and socioeconomic factors.
Reference values of haematological indices are necessity for the assessment of health in routine assessment of anaemia, infection and blood disorders. They are important ad surrogate markers of assessment of immune status, disease progression and response to treatment.
The values of haematological parameters are affected by a number of factors even in apparently health population. These factors include age, sex, ethnic background, body build and social, nutritional and environmental factors especially altitude (5).
Reference values for the elderly may differ from those of younger (6). Reference values haematological indices used in Africa are derived from data collected from population living in the developed countries (7,8). Few studies with African population that have been reported indicated differences in haematological reference values compared with those for the populations in developed countries (9,10,11,8).
Despite considerable amount of data published concerning the haaematological status of the aged clinicians are still confronted with the problem of ‘‘Normal’’ or ‘‘physiological’’ values in these subjects. It has been a well established practice to determine the normal value of various haematological parameters in different parts of the world (12). In interpreting an individual laboratory test result, the clinician usually compares the reported values with the reference values. In appropriate reference values may increase the risk of either unnecessary additional investigation or failure to detect underlying disease (13).
There is limited information available on these haematological parameters and coupled with the fact that reference values from other parts of the world and Nigeria are used to interpret the values of these parameters in aged in health institutional Laboratories in Zaria, Kaduna State. The estimation of profile of constituents of blood in the healthy elderly men and women will go a long way to contribute to a better understanding of physiological changes in this area. The haematological parameters so established will provide a better interpretation of haematological Laboratory results in the elderly men and women.
The aim of this study is to estimate the reference interval for commonly used haematological parameters in an adult (60-85 years) population in Zaria, Northern Nigeria and to compare the haematological parameter in the elderly and the young adult control (20-30 years).
MATERIALS AND METHODS
The sample size of the present study was determined using Yaro Yamane’s formula (1998). Four hundred (400) apparently healthy adult male and female Nigerians comprising of 210 males and 190 females aged 60-85 years and 210 apparently healthy. Young adults aged 20-30 years, comprising of 108 males and 102 females were used as control subjects in this study. Criteria for the selection of volunteers include apparently healthy, no recent history of blood loss, HIV negative, no malaria parasite in the blood, no urine protein or sugar, no parasites in the fecal samples, must not have received blood transfusion in the previous six months, no cigarette smoking and alcohol intake.
The study was performed after obtaining permission from the Ethical Committee of Ahmadu Bello University, Zaria and after an informed consent of the volunteers.
Four (4) ml venous blood was obtained from each subject using needle and syringe, 2ml of the blood were placed in EDTA bottles and was used determine haematological parameters using Haematology Analyser (Cell Dyn 400, Abbolt Lab) the remaining two (2) ml of the blood were used for ESR (Westergen method, 1918).
The haematological parameters analysed were red blood cell (RBC) counts haemaglobin contraction, packed cell volume (haematocrit), white blood cell (WBC) Count, Platelet Counts, differential white blood cell counts, mean corpuscular volume (MCV), Mean corpuscular haemaglobin (MCH) and Mean Corpuscular haemaglobin concentration (MCHC).
The data was analysed using statistical program ‘statistic window 3).1. The reference ranges (95% ranges) for all parameters were established by the standard parametric method (Mean ± SEM). Comparison of mean values between age groups was made by students T- test. The error probability of P < 0.001 was considered significant.
The medium ages of the subjects were 69.1 and 68.8 years for apparently healthy aged males and females respectively (Table I).
The haematological parameters of apparently healthy elderly males and females shown in table II. The mean haemaglobin values were 13.4 ± 0.34g/dl and 12.3 ± 0.07g/dl for males and females respectively. The mean haematocrit were 39.7 ± 0.34 and 36.6 ± 0.23, mean RBC counts were 4.2 ± 0.03 and 3.8 ± 0.03, WBC counts values were 5.5 ± 0.07 and 4.9 ± 0.05 and Platelet Counts values were 182.5 ± 2.08 and 161.8 ± 2.18 for males and females respectively. In the Young adult control the mean haemoglobin values for males and females were 14.6 ± 0.07 g/dl and 13.9 ± 0.08 g/dl, mean RBC counts values were 5.3 ±0.36 x 10-12/L and 4.4 ± 0.05 x 1012/L, Platelet values were 237.5 ± 3.12 x 109/L aand 214.5 ± 3.10 x 109/L for males and females respectively (Table III)
The mean values of RBC counts, haematocrit, WBC counts, platelet counts and Neutrophils were significant lower in the apparently healthy elderly males and females (P<0.001) than in young adults (controls as shown in table IV.
The mean values of ESR, MCV, MCH, Eosinophils, monocytes and lymphocytes were significantly increased in the apparently healthy elderly males and female compared to the apparently healthy young adults control (P<0.001) as shown in table III. There were no significant differences in the mean values of MCV 9P<0.126), MCHC (P<0.61), Monocytes (P<0.123) in both apparently healthy elderly females and the young adults control females
No significant differences were observed in the mean values of MCHC (P<0.367) and basophils (P=.659) in both apparently healthy elderly males and the young adults control males.
HB, RBC Counts, PCV, WBC Counts , platelet counts, ESR, MCH, Neutrophils and Lymphocytes showed significant sex related differences between apparently healthy elderly males and females (P<0.001) as shown in Table II. The values were all higher in apparently healthy than in females.
There were no significant differences observed in the mean values healthy of MCV (P<0.040), MCHC (P=0.098) Monocytes (P=0.994) and basophils (P=0.492) among the apparently healthy young adults males and females. The mean values of Hb, PCV, WBC Count, RBC counts, Neutrophils and lymphocytes were higher in apparently healthy young adult males than the females (P<0.001). there were however, no observed differences in mean values of MCHC (P=0.311) monocytes (P=0.098), eosinophils (P=0.820) and basophils (P=0.188) in the same group.
DISCUSSION AND CONCLUSION
This study suggests that haematologial parameters estimated between the apparently healthy elderly males and females than in apparently healthy young adults control (P<0.001). The mean values of haemoglobin, haematocrit, RBC abd WBC counts, Neutrophils, and Platelet, counts estimated in this study are lower than those reported in the Caucasian. Many workers have documented significant differences in the values obtained in Nigerians compared with the Caucasian values (14, 15, 16,17).
The values of haematological parameters observed in this study were in agreement with the World Health Organization (WHO) Criteria for haematological values among the blacks (18, 19).
The findings are also in agreement with those reported by Herman, ( 20) and Wallen,(21). They reported that slight decline in haemoglobin level in the elderly men and women does not necessarily indicate disease and that the lower reference limits for both men and women were 11.5g/dl from age 85 years. in Ghana, (8) reported mean Hb values of 14.2g/dl and 12.0g/dl for elderly men and women.
The higher mean values of MCV and MCH observed in this study is in agreement with the finding of the Brain, (11), they also observed that mean values of MCV and MCH were higher in the elderly than the young adults. There were no significant age or sex related changes for mean values of MCHC. This is in agreement with the finding of Herman et al, (20), and in contrast with other findings reported which show higher MCHC in the elderly than the young adult (11).
The above observation may be as a result of the replacement of the red marrow by fatty (Yellow marrow).