Influence of Perceived Stress on Hemoglobin Concentration

 

Subbalakshmi NK*, Sunandha S

Department of Physiology, Kasturba Medical College, Mangalore, Manipal University, Mangalore -575001, India.

 

ABSTRACT:

High rate of anemia and stress is reported in medical students. Experimental studies in animals have indicated that psychological stress may lead to iron deficiency anemia. Therefore we investigated the association between perceived stress and hemoglobin concentration in medical students. 84 medical students aged   between 19-21 years were studied. The main parameters measured were hemoglobin concentration, perceived stress and diet. The perceived stress was measured using Cohen’s perceived stress scale. Diet was estimated by a dietician’s questionnaire. Hemoglobin was measured by digital hemoglobin meter using capillary blood. In male subjects, hemoglobin concentration below 13.5 gm% and in female subjects below 11.5 gm% was taken as low (group A) and the rest were considered as with normal hemoglobin (group B). Data analysis included unpaired t test, Mann- Whitney U test and Chi-square test. Level of significance was taken at p value less than 0.05. Hemoglobin concentration was negatively correlating with perceived stress score and positively correlating with diet score (r = - 0. 26, p = 0.015; r = 0.25, p = 0.018 respectively). Mean perceived stress score of group A was higher compared to group B (Mann-Whitney U-statistic = 614.00, p = 0.0376). Frequency of subjects with high perceived stress score in group A was higher compared to group B (Chi-square = 8.0188, p = 0.00463). The   diet score did not differ significantly between group A and group B. High perceived stress may contribute to development of iron deficiency anemia in undergraduate medical students.

 

 

 

 

 

INTRODUCTION:

Hemoglobin is an essential biochemical required for transport of oxygen to tissues. Thus low hemoglobin reduces oxygen carrying capacity of erythrocytes. Of late, several studies have observed higher incidence of iron deficiency anemia in university student population. Shill KB et al   have observed iron deficiency anemia in 55.3%  of university students and report   higher incidence of it  among students aged 20-22 years.¹ Manjula VD et al have reported   iron deficiency anemia in 19.13 % of female medical students.² Pandey S et al have reported nutritional anemia in 30.2% including both female and male  medical students.³

 

In our previous study in apparently healthy  medical undergraduate students low hemoglobin concentration was observed in 39.28% of study subjects.⁴ These observations suggest that university students are vulnerable to anemia and thus necessitate to probe  the influencing factors of anemia in student population. Some of the studies investigating the causes of anemia, have observed close association between physical stress such as surgical trauma, long duration space exploration missions and iron deficiency anemia.^{5, 6} A more recent study in the animal model has demonstrated that pure psychological stress can cause decrease of serum iron and consequently affect erythropoiesis.⁷ College students, entering into medical course face academic and clinical challenges.  Accordingly several studies have reported higher incidence of stress level and ill health in medical students. ^8-11 Thus this study was taken up to find the influence of perceived stress on hemoglobin concentration in medical undergraduate students.

 

MATERIAL AND METHODS:

This was a cross sectional study done in 84 apparently healthy undergraduate medical students aged between 18-20 years and of either sex. This study had institutional ethical committee clearance and written consent was obtained from study participants. Based on the hemoglobin concentration study subjects were divided into two subgroups: Low hemoglobin group (group A): Hemoglobin concentration below 13.5 gm% for males and 11.5gm% for females; Normal hemoglobin group (group B): Hemoglobin concentration 13.5gm% or above for males and 11.5gm% or above for females.

 

Study Protocol:

In all the study subjects, all   the study procedures were done between 4-6 pm.  Sheldon Cohen’s Perceived Stress Scale was used to measure and assess the severity of stress in study subjects.¹² The study subjects who scored less than 13 in Cohen’s Perceived scale were considered as free from stress, 13-20 score was taken as mild to moderate stress level and above 20 was taken as severe stress.¹² The diet pattern was scored appropriately by a questionnaire prepared by a qualified dietician based on Dietetics. ¹³

 

Study Procedures:

The particulars regarding age and overall health of study participants were enquired into while interviewing them individually. In any of the subjects with any known clinical condition which might affect study findings were excluded from the study. The eligible study subjects were then asked to fill the required questionnaires on perceived stress¹² and nutritional status.¹³ Height and weight of each subject was measured accurately. Body mass index was calculated as weight (in kg) divided by square of height (in meters). Hemoglobin estimation was done using digital hemoglobinometer. Estimation was done from capillary blood, collected from subject’s finger prick with a glucopen with aseptic precautions. Hemoglobin level below 13.5gm% for males and 11.5gm% for females was considered as low.¹⁴

 

Statistical Analysis:

Statistical tests included unpaired t test, Mann-Whitney U test and Chi-square test. p value less than 0.05 was taken as significant.

 

RESULTS:

Data was collected from 84 apparently healthy medical undergraduates on height and weight, perceived stress level and diet. Data collected on these parameters is presented below separately with suitable side headings.

 

Baseline Characteristics of the Study Subjects:

Data on continuous variables is presented as mean ± SD. Mean age of the study group was19.69 ± 0.878 years.  Their body mass index was 23.12 ± 4.44 kg/m2. Their hemoglobin content was 12.60 ± 1.68gm%. Their diet score and perceived stress score was 32.59 ± 5.87, 19.97 ± 5.69 respectively. There were 44 females and 40 males.

 

Incidence of Low Hemoglobin in Study Subjects:

In the midst of   84 study participants, 32 were having hemoglobin concentration below normal (39.28%).  Among the 40 males 12 subjects had hemoglobin below 13.5 gm% (30%). Among the 44 females 21 subjects had hemoglobin concentration below 11.5 gm% (47.72%)

 

Correlation of Hemoglobin Concentration with Diet Score, Body Mass Index and Perceived Stress Score:

 Data on correlation of hemoglobin concentration with diet score, body mass index and perceived stress score is presented in table 1. Diet score was positively correlating with hemoglobin concentration (table 1). Perceived stress was negatively correlating with hemoglobin concentration (table 1). Body Mass Index was not correlating significantly with hemoglobin concentration (table 1).

 

Correlation of Perceived Stress Score with diet Score and Body Mass Index:

Diet score and body mass index were not correlating with perceived stress (r = -0.047, p = 0.671; r = 0.046, p = 0. 677 respectively).

 

Comparison of Diet Score and Perceived Stress Score between group A (with low Hemoglobin concentration) and group B (with Normal Hemoglobin Concentration):

Among the study subjects 33 were having low hemoglobin level and 51 were having normal hemoglobin content. The data on perceived stress score and diet score in subjects between group A and group B is presented in table 2.  Perceived stress score of subjects in group A had significantly higher perceived stress score compared to group B. Diet score and body mass index of group A was not significantly different compared to group B.

 

Table 1: Correlation of Hemoglobin level with Body Mass Index Diet and Perceived Stress Score   (n = 84)

Variables	Correlation Coefficient (r)	p -value
Body mass index (kg/m2)	0.131	0.234
Diet score	0.257	0.018
Perceived stress score	-0.26	0.015

 

Table 2: Comparison of Assessed Parameters between with low Hemoglobin Level Group and Normal Hemoglobin level Group  (Values are mean) ± SD

variables	Low hemoglobin group ( n = 33)	Normal hemoglobin group  (n = 51)	t value	p- value
BMI (kg/m2)	23.85 ± 5.08	22.64 ± 3.94	1.22	0.22
Stress score *	21.48 ± 6.03	19± 5.28	1.98	0.05
Diet score	31.96 ± 5.07	33 ± 6.36	0.78	0.43

* Mann-Whitney U-statistic = 614.00;   P value is 0.0376

 

Comparison of Frequency of subjects with high stress level between group A (with low hemoglobin concentration) and group B (with normal hemoglobin concentration):

According to score obtained in perceived stress scale, study subjects were separated into three groups. The subdivisions were below 13 score; between 13-20 score; and above 20 score. Distribution of subjects based on these subdivisions in hemoglobin low (group A) and normal level group (group B) is presented in table 3. Frequency of subjects with 13-20 and above 20 score was higher in low hemoglobin group compared to normal hemoglobin group. Frequency of subjects with below 13 stress score   of low hemoglobin group was not significantly different compared to   normal hemoglobin group (table 3).

 

Table 3: Frequency of subjects with high level stress in with low and normal hemoglobin level

Stress level	Low hemoglobin group ( n= 33)	Normal hemoglobin group  ( n=51)	Chi-square statistic	p- value
Stress score less than 13	3	7	0.4103	0.521793
Stress score between 13-19	6	23	6.4214	0.011275
Stress score more than 20	24	21	8.0188	0.00463

 

 

Frequency of Under - Weight Subjects in Low Hemoglobin Concentration Group:

In 10 subjects body mass index was less than 18.5 Kg/m2. Among them two male subjects and one female subject was with below normal hemoglobin concentration.

 

DISCUSSION AND CONCLUSION:

Medical students surpassing adolescence and entering into adulthood are exposed to several day-to-day challenges. In them higher incidence of anemia and stress level is reported. Therefore we studied the influence of stress and diet on hemoglobin concentration. In the present study negative correlation was observed between hemoglobin concentration and perceived stress score (table 1). Mean perceived stress score of low hemoglobin group was significantly higher compared to group with normal hemoglobin level (table 2). Frequency of subjects with high stress score was higher in low hemoglobin level group compared to group with normal hemoglobin level (table 3). Nakamura k et al’s study on the effect of mental stress on hemoglobin concentrations in the trapezius muscles of 20 healthy females reports that mental stress may affect hemoglobin concentration. ¹⁵ Upon an investigation on effect psychological stress on hemoglobin concentration, investigators report that psychological stress can decrease serum iron and subsequently erythropoiesis may be affected. ¹¹ To best of our knowledge there are no studies investigating the association between perceived stress and low hemoglobin concentration. Therefore based on our study findings along with findings of experimental studies we speculate that stress can adversely influence oxygen carrying capacity of the erythrocytes. However more studies are required on this line to confirm our study findings. In the present study there was no association between hemoglobin content and body mass index (table 1).  Mean body mass index of low hemoglobin group was comparable to group with normal hemoglobin concentration (table 2). Of the 10 underweight subjects only three were with low hemoglobin level. The reports on association between underweight and low hemoglobin concentration is conflicting. In the study of Shill BK et al, Sachin P et al the underweight students were found more anemic than the overweight and obese subjects.^{1, 3} On the other hand Manjula VD et al has not found any association between hemoglobin concentration and low body mass index.² However, our study findings is consistent with the findings of Manjula VD et al’s investigation and do not confirm the findings of Shill BK et al’s and Sachin et al’s investigations. Our investigation observed that hemoglobin concentration is positively correlating with diet (table 1). Nevertheless, mean diet of low hemoglobin concentration and groups with normal hemoglobin concentration was comparable (table 2).  Thus we hypothesize that even though appropriate diet is essential for proper hemoglobin synthesis; there are other major factors which may lower hemoglobin concentration despite appropriate diet. Our study is with certain limitations. This study is an offshoot study of primarily investigating the role of hemoglobin and other risk factors of elevated blood pressure. Therefore all the parameters pertaining to iron deficiency could not be collected.  However lower hemoglobin concentration being one of the major determinants of iron deficiency anemia it could be concluded that perceived stress may contribute to development of anemia.

 

CONFLICT OF INTEREST:

The authors declare no conflict of interest.

 

REFERENCES:

1.     Shill KB, et al. Prevalence of Iron-deficiency Anemia among University Students in Noakhali Region, Bangladesh. J Health Popul Nutr 32 (1); 2014:103-110.

2.     Manjula V D, et al. Prevalence of Anemia Among Female Undergraduate Students of Government Medical College Kottayam, Kerala. Int J Med Health Sci. 3(2); 2014:133-138.

3.     Sachin P, Arun S. A Cross Sectional Study of Nutritional Anaemia among Medical Students in a Medical College, at Bilaspur, Chhattisgarh. National Journal of Medical Research 3(2); 2013; 143-146.

4.     Sunandha S, Subbalakshmi NK. Pre-Hypertension in Apparently Healthy Young Adults: Incidence and Influence of Hemoglobin Level. Journal of Clinical and Diagnostic Research. 9(11); 2015: CC10-CC12.

5.     Madhumita N, et al. Stress and its risk factors in medical students: an observational study from a medical college in India. Indian Journal of Medical Sciences 66 (1 and 2); 2012:1-12.

6.     Eva EO, et al. Prevalence of stress among medical students: a comparative study between public and private medical schools in Bangladesh. BMC Res Notes 8; 2015:327.

7.     Iqbal S, et al. stress, anxiety and depression among medical undergraduate students and their socio-demographic correlates. Indian J Med Res 141; 2015: 354-357.

8.     Subbalakshmi NK, et al.  Perceived Stress Level in Regularly Exercising and Sedentary Undergraduate Medical Students. International Journal of Health Sciences and Research 5 (7); 2015:156-160.

9.     Nikolova-Todorova Z, Troic T. Effect of surgical trauma on patient nutritional status. Med Arh. 2003; 57(4 Suppl 1); 2003:29–31.

10.   Smith SM, et al. The nutritional status of astronauts is altered after long-term space flight aboard the International Space Station. J Nutr. 135(3); 2005:437–43.

11.   Wei C,  et al. Effects of psychological stress on serum iron and erythropoiesis Int J Hematol  88;2008: 52-56.

12.   Cohen S, Kamarck T, Robin Mermelstein R. A Global Measure of Perceived Stress. Journal of Health and Social Behavior 24; 1983: 385-396.

13.   Shrilakshmi B. Diet in cardiovascular diseases. In: Dietetics, edited by Shrilakshmi B.  New Age International Publisher.2011; 6th ed: 246-274.

14.   Ghai CL. Estimation of Hemoglobin. In A Textbook of Practical Physiology, edited by Ghai CL. Jaypee Brothers medical publishers(P) Ltd, New Delhi.2007;7th ed: 36-48.

15.   Nakamura K, Taoda K, Kitahara T, Tsujimura H, Nishiyama K. Effect of mental stress on hemoglobin dynamics in trapezius muscles. Sangyo Eiseigaku Zasshi. 49(6); 2007:225-33.

 

 

 

 

Received on 07.09.2016          Modified on 11.11.2016

Accepted on 20.11.2016        © RJPT All right reserved