Time trends of haemologbin levels and anaemia prevalence in infancy in a total community

Public Health (1992), 106, 11 18

© The Society of Public Health, 1992

Time Trends of Haemoglobin Levels and Anaemia Prevalence in Infancy in a Total Community R. Gofin, H. Palti and B. Adler Department of Social Medicine, Hadassah Medical Organization, Hebrew University-Hadassah School of Public Health and Community Medicine, Jerusalem

In order to determine the trends in haemoglobin (Hb) levels and the prevalence of anaemia in infancy in an entire community, 3,147 infants aged 9-11 months attending the Mother and Child Health Clinics of the teaching and research Health Center in Kiryat Hayovel, Jerusalem, were examined. From 1971 to 1979 infants diagnosed as anaemic were given treatment. From 1980 to 1988 supplement was given to all infants from the age of 3 to 12 months. There was a mean increase of 0.6 g/dlHb between the two periods, with a larger increase in the Hb levels in 1980-88 as compared to 1971-79 ( P - .0001). The prevalence of anaemia < 11 g/dlHb decreased from 36% in 1971 to 27% in 1979 and to 19% in 1988. The prevalence of anaemia < 10 g/dlHb decreased from 13.7% in 197t to 8.7% in 1979 and to 3.6% in 1988. The time trend is probably due to changes in the socio-demographic characteristics of the population, an overall change in infant feeding practices in relation to iron source and the supplementation programme.

I r o n d e f i c i e n c y a n a e m i a is t h e m o s t c o m m o n c a u s e of n u t r i t i o n a l a n a e m i a s in y o u n g c h i l d r e n . Its p r e v a l e n c e for c h i l d r e n up to t h e age of 5 y e a r s is e s t i m a t e d at a b o u t 51% in d e v e l o p i n g c o u n t r i e s a n d 12% in m o r e d e v e l o p e d r e g i o n s . 1 T h e m o s t a f f e c t e d a r e c h i l d r e n o f low s o c i o - e c o n o m i c status. 2,3 I r o n d e f i c i e n c y is c h a r a c t e r i s e d b y b o t h h a e m a t o l o g i c a l ( a n a e m i a ) a n d n o n - h a e m a t o l o g i c a l m a n i f e s t a t i o n s . T h e r e is an effect o n g r o w t h , o n t h e g a s t r o i n t e s t i n a l t r a c t 4 a n d o n b r a i n d e v e l o p m e n t with c o n s e q u e n t effects o n b e h a v i o u r a n d inteUigence, s 8 T h e m o s t c o m m o n causes of iron d e f i c i e n c y a n a e m i a a m o n g c h i l d r e n a r e k n o w n to b e d i e t a r y factors such as s h o r t d u r a t i o n o f b r e a s t f e e d i n g , t h e use o f c o w ' s m i l k in e a r l y i n f a n c y a n d t h e c o n s u m p t i o n o f f o o d s o r f o r m u l a s t h a t h a v e p o o r i r o n c o n t e n t ; low b i r t h weight; b l o o d loss; g e n e t i c traits; a n d i n f e c t i o n s . 9 I n the p a s t two d e c a d e s a d e c l i n e in t h e p r e v a l e n c e o f a n a e m i a has b e e n n o t e d in s o m e c o u n t r i e s . In the U S A d a t a f r o m the N a t i o n a l H e a l t h a n d N u t r i t i o n E x a m i n a tion S u r v e y , c o n d u c t e d f r o m 1976 to 1980, s h o w e d low r a t e s o f a n a e m i a , 5 . 7 % , a m o n g c h i l d r e n a g e d 1 - 2 y e a r s . 1° C h a n g e s a r e n o t o n l y e v i d e n t a m o n g m i d d l e - c l a s s c h i l d r e n H b u t also a m o n g d e p r i v e d p o p u l a t i o n s . C h i l d r e n p a r t i c i p a t i n g in t h e S p e c i a l S u p p l e m e n t a l F o o d P r o g r a m f o r W o m e n , I n f a n t s a n d C h i l d r e n ( W I C ) in t h e U S A 12 s h o w e d a d e c l i n e o f a b o u t 50% in t h e p r e v a l e n c e o f a n a e m i a o f less t h a n 10.3 g / d l h a e m o g l o b i n ( H b ) . T h e s e c h a n g e s w e r e a t t r i b u t e d to i m p r o v e d i r o n n u t r i t i o n in infancy and early childhood, greater frequency and duration of breast feeding, and i n c r e a s e in t h e use of i r o n - f o r t i f i e d f o r m u l a s a n d i r o n - f o r t i f i e d c e r e a l s . Correspondence to: Rosa Gofin MD, MPH, Hadassah School of Public Health and Community Medicine, PO Box 1172, Jerusalem 91010, Israel.

12

R. Gofin et al.

Changes in the prevalence of anaemia < 11 g/dlHb have also occurred in Israel. In the 1950s anaemia rates varied from 50-80% among infants from low socio-economic groups to only 20% among those in higher socio-economic groups. 3 Recent studies have shown a decline from 50% in 1979 to 21% in 1988 in the rate of Hb < 11 g/dl in a low socio-economic semirural area. These changes were due to an intervention supplementation programme and to extensive use of iron-fortified formulas and cereals. 13 In the teaching and research Community Health Center of Hadassah in Kiryat Hayovel, a western neighbourhood in Jerusalem, Community Oriented Primary Care (COPC) programmes have been developed since the early 1970s. The Promotion of Growth and Development programme 'PROD', TM is delivered through the Mother and Child Health (MCH) clinics in the Center. The objectives of the programme are: a) the promotion of health through improved nutrition, protection against infection and social stimulation and b) prevention of retardation in physical growth and in behavioural and intellectual development, especially among socially disadvantaged groups. Because of a high prevalence of anaemia among infants, an anaemia control programme was introduced in 1969 within the above-mentioned framework. All children were screened for anaemia at 9 months of age and those found to be anaemic were treated with iron preparations. In 1980 the above described secondary prevention programme was changed to a primary prevention programme: all children attending the MCH clinics receive iron supplementation from 3 months to 1 year of age. The present study describes the time trends in Hb levels and anaemia rates in infancy from 1971 to 1988. Population and methods The study was carried out in Kiryat Hayovel, a western neighbourhood of Jerusalem (population 15,000). The settlers in this community, which was established in the 1950s, originated from about 25 countries in Africa, Asia, Europe and America. At that time, they were of low socio-economic status and with low levels of formal education, particularly those who came from North African and Asian (Middle Eastern) countries. The different cultural patterns that characterised these families with respect to life-styles and rearing practices have now been blended into a more homogenous society while still maintaining ,their different cultural backgrounds. The changing socio-demographic characteristics for the period under study--1971 to 1988--are shown in Figure 1. The number of births decreased during these years. In the 1980s all the infants and the majority of the mothers were Israeli born. Comparing the mother's educational level and social class distribution as measured by an adaptation of the British Registrar Generat 15 there is an indication towards both higher social class and educational level from the early 1970s to the 1980s. All infants receive care at the MCH clinics of the Hadassah Community Health Center, which are accessible and available to all children living in a geographically defined area. Birth notifications are received on an ongoing basis from the hospitals, where 100% of births take place. Continuous demographic surveillance is carried out in this population by the MCH team. The number of births varied from 300 at the beginning of the period to 180 in the late 1980s. There is a mobility of the population of about 25% in the first year of life. The socio-demographic characteristics of those

Haemoglobin Levels and Anaemia in Infancy

13

80f 70 60 50 40

iiiiiii~iiV//Z NNV///,

30

iiiiiiiiiii

20 10 0

Education ->13 y

Israeli born 1971-74 n = 846

~

1975-79 n = 1016

~

198044 n = 854

Social class I-II 1"---7 1 9 8 5 - 8 8 n = 431

Figure 1 Trends in selected socio-demographic characteristics of the population: mother's origin, mother's education and social class who leave the area are similar to those who remain. Data on Hb levels and anaemia were available from 1st June 1971 to 31st June 1988. All infants were examined between 9-11 months of age. The response rate for Hb examination among infants still living in the area ranged from 80% to 90% over the study years. Capillary blood was taken by finger pricking. Determination of Hb was done within 5 hours by the cyanohaemoglobin method, by the Klett machine for the years 1971-78 and by the Coulter from 1979 onwards. Quality control was carried out over the years by checking intra- and interobserver variation and standardization with the international standard of Hb. Comparison between the Klett and Coulter evaluations showed repeatedly high correlations. From 1971 to 1979 treatment was provided to all infants with a level of < 11 g/dlHb at 9 months of age. Syrup of ferrous sulphate was prescribed, which provided 40-60 mg of elemental iron per day for a period of 3 months. During the following period from 1980-88 iron supplement (7-15 mg elemental iron/day) was given to all infants from 3 to 12 months of age. Breast-fed infants received supplement from the fifth month only. The iron supplement preparation included ferrous carbonate 15 mg with vitamin C 100 mg. Low birth weight infants ( 7 % - 8 % of all births during the years under study) received 2 mg/Kg/day of elemental iron from the second month. Children with a level of Hb < 11 g/dl at 9 months received iron treatment: 50 mg ferrous carbonate per day for 3 months. Compliance with the supplementation regime was monitored for the years 1983-88 based on the report of the mother at the monthly visit to the MCH clinic. There are about 11.5 routine visits to the clinic during the first year. Compliance was categorised into the following groups: 'good' (regular supplementation for ~>5 months); 'fair' (regular supplementation for < 5 months or irregular for >~ 5 months) and 'poor' compliance (irregularly for < 5 months or not given). In addition to the medication, nutritional advice was provided. Mothers were encouraged to breast feed for six months t6 and to introduce iron-fortified formula and

R. Gofin et al.

14

cereals and iron-rich foods during the second half of the first year, e.g. meat, soya beans etc. Feeding with cow's milk was discouraged for the first year of life. The prevalence of haemoglobinopathies such as thalassaemia are infrequent in this population and the families with this condition are mostly known. Data was analysed by the SPSSX program.17 Moving averages were calculated for Hb levels and anaemia prevalence in order to get a smooth curve. The least-squares method was used to fit a curve to the changes in Hb level for the periods 1971-79 and 1980-88. Analysis of variance was done to determine the changes in H b levels over the years, controlling for the possible effects of confounding variables such as origin, social class, mother's educational level, sex, birth rank ( n u m b e r of previous live births) and birth weight. Haematocrit levels are not presented since they followed the same patterns as the Hb levels. Results

The trends in mean Hb levels for the entire period are presented in Figure 2. The standard deviation of the H b levels varied from 0.9 to 1.1 over the study years. A mean increase of 0.6 g / d l H b is noticed from 11.2 g/dl in 1972 to 11.8 g/dl in 1987. The increase, controlling for mother's origin and education, social class, the infant's sex, birth weight and rank was statistically significant ( P = .0001). It was larger in the period 1980-88 as compared with 1971-79 ( P = .0001). The mean increase among low birth weight infants was 1.1 g/dl. Changes among those infants were unstable due to the small n u m b e r of cases. The association of the socio-demographic variables and birth weight to the mean Hb levels over the years under study are presented in Table I. For the period 1983-88 compliance with the supplementation regimen was introduced into the analysis. For the period 1971-79 the mean H b levels varied significantly with social class: the higher the social class the higher the mean Hb level ( P = .002). First-born 12.40

lSupplementation

-

12.20 12,00

/

//

//~-.\

~\

x\

//

//t

///

/

=_f_ 1.8o g 11.6o '~ 11.40 11,20

i

//

11.00i 10.80

0a

I

72

~

73 74

I

75

J

76

[

77

[

78

All infants

l__

I

79 80 Years

_J~

81

....

1

82

[

83

I

84

t

[

85 86

I

87

LBW infants

Figure 2 Mean Hb levels among 9-month-old infants by year (1972-1987)

Haemoglobin Levels and Anaemia in Infancy

15

Table I The effect of selected socio-demographic variables, birth weight and compliance on mean Hb levels for the periods 1971-79 and 1983-1988. Analysis of variance. 1971-79 n

1983-88

Adjusted mean

n

Adjusted mean

Mother's origin Asia Africa Europe-America Israel p

193 344 219 851

11.3 11.4 11.3 11.4

12.0 12.0 ll.9 11.8

31 38 91 326

.705

.449

Mother's education 0-8 9-12 /> 13 P

279 823 505

11.3 11.3 11.4

11.7 11.8 11.9

35 213 238

.167

.562

Social class I-1I III 2 III 3 IV-V P

504 494 483 126

11.5 11.4 11.3 11.0

226 107 135 18

.002

11.9 11.9 11.7 11.7 .416

Birth rank* 0 1 /> 2 P

557 541 509

11.5 11.3 11.3

194 128 164

.002

11.9 11.7 11.8 .171

Sex Male Female P

829 778

11.2 11.5

261 225

.000

11.9 11.8 .583

Birth weight (g) < 2500 2500-2999 /> 3000 P

103 374 1130 .000

11.3 11.1 11.4

37 113 336

12.1 11.7 11.9 .060

Compliance Good Fair Poor P

-

-

79 251 156

12.1 11.9 11.7 .018

*Number of previous live births

babies p r e s e n t e d significantly h i g h e r m e a n H b levels as c o m p a r e d with o t h e r r a n k s ( P - - . 0 0 2 ) . F e m a l e s had a m e a n H b level of 0.3 g/dl h i g h e r t h a n boys ( P = .000). Low b i r t h weight b a b i e s s h o w e d m e a n H b levels closer to the levels of b a b i e s whose

R. Gofin et al.

16

birth weight was 3000 g or more. No significant differences in mean Hb level were found by mother's educational level and origin. For the period 1983-88 there were not statistically significant associations with the socio-demographic variables and birth weight. A statistically significant association was found between compliance with the supplementation programme and mean Hb level: the difference in mean Hb level between 'poor' compliance and 'good' compliance was 0.4 g/dl Hb. The prevalence of anaemia (Figure 3) defined as < 11 g/dlHb decreased from 36% at the beginning of the period (1972) to 27% at the end of the 1970s. During the period 1980-87 there was a further decrease to 19%. The total decrease from 1972 to 1987 was 47%. The prevalence of anaemia defined as < 10 g/dlHb decreased from 13.7% to 8.7% in the first period; it further decreased to 3.6% by 1987. The total decrease from 1972 to 1987 was 74%. If considering a cut-off point of 10.3 g/dl, as done by the WlC programme in the USA, ~2 the decrease in anaemia rate in our community was 68% from 17.8% to 5.7%. Among low birth weight infants the anaemia rate was 38% in 1972. There have been no anaemia cases in the last four years. This finding has to be considered cautiously since the number of low birth weight infants studied was small (n = 22). Discussion

The present study deals with the time trend of anaemia in infancy during a 17-year period in an entire community. During this period the prevalence of anaemia has declined by 47% and the mean Hb level has increased by 0.6 g/dl. The rate of anaemia in the rest of the country in 1986 was 45% .3 At the beginning of the 1970s, when the intervention programmes were introduced into the MCH practice of the Hadassah Community Health Center, no gross malnutrition was observed among infants as measured by weight and length. TM The high prevalence of anaemia mainly due to iron deficiency indicated a nutritional deficiency, most of which was mild.a9 Low iron intake was due to extensive use of 40-

Supplementation

30

20

10

I ~ 72 73

I

f

I

I

I

I

74

75

76

77

78

79

1__1~_ 80

81

I 82

83

L_J__l__k_ 84

85

86

87

Years

<11

g/dl H b

....

<10

g/dl Hb

Figure 3 Prevalence of anaemia (%) among 9-month-old infants by year (1972-t987)

Haemoglobin Levels and Anaemia in b~fancy

17

cow's milk, with no availability of iron-fortified foods, and short duration of breast feeding. 17 The favourable time trends observed in this community can be attributed to several factors such as changes in the population structure, changes in feeding practices and to the primary prevention programme. As for the changes in the population structure throughout the study years, the educational and social class level was higher in the 1980s than in the 1970s. Linked with the socio-demographic changes in the population, changes in the feeding patterns of infants occurred, since they are related to social class variables. The percentage of mothers breast feeding and the duration of breast feeding increased; use of cow's milk declined; use of iron-fortified formulas and foods became the norm in the first year of life. For example, in 1973 breast feeding prevalence was 13% at 13 weeks and 7% at 26 weeks. 17 In 1981 a structured breast feeding promotion programme was introduced. 16 The evaluation of the programme in 1985 showed that the percentage of mothers breast feeding at 13 weeks increased from 28% in 1981 to 41% in 1985 and at 26 weeks increased from 10% to 29% respectively. In addition, iron-fortified formulas became available in the 1980s at almost the same price as cow's milk, thus the use of cow's milk has declined. The improvement in Hb levels in the 1980s is probably due to the joint effect of the above-mentioned population and feeding-pattern changes and the introduction of the primary prevention programme. The introduction of iron supplementation, together with information and advice on the importance of iron in infancy, may have increased the mother's awareness with regard to the prevention of anaemia. During this period a steeper increase in the Hb level occurred. A high percentage of mothers were fair and good compliers, therefore some of this increase can be attributed to the primary prevention programme. The independent effect of the supplementation programme could only be studied by a controlled trial. Since the national policy is to give supplementation to all infants, an adequate control group cannot be selected. The improvement in Hb levels observed among low birth weight infants was evident during both study periods, since iron supplementation has been recommended since 1971. This high-risk group of infants develops anaemia frequently. Due to accelerated rate of growth and the consequent rapidly expanding blood volume, their iron stores are quickly exhausted, a° In conclusion, there has been a decrease of 47% in the rate of anaemia in infancy over a period of 17 years in an entire community. The improved iron status was probably due to multiple factors: improvement in the socio-economic characteristics of the population, leading to increased awareness in the prevention of anaemia; improved iron nutrition achieved by the increased percentage of women who were breast feeding, and prolonged duration and an overall change in infant feeding practices as related to iron source; introduction of the iron supplementation programme for all infants.

References

1. De Maeyer, E., Dallman, P., Gurney, J. M. et al. (1989). Preventing and Controlling Iron Deficiency Anemia through Primary Health Care. Geneva: WHO. 2. Committee on Nutrition (1976). Iron supplementation for infants. Pediatrics, 58,765-768.

18

R. Gofin et al.

3. Palti, H. & Tulchinsky, T. H. (1988). Anemia as a public health problem in Israel, Public Health Reviews, 16,215-250. 4. Leibel, R. L. (1977). Behavioral and biochemical correlates of iron deficiency. Journal of the American Dietetic Association, 71,398-404. 5. Oski, F. A. & Honig, A. S. (1978). The effects of therapy on the developmental scores of iron deficient infants. Journal of Pediatrics, 92, 21-25. 6. Oski, F. A., Honig, A. S., Helu, B. et al. (1983). Effects of iron therapy on behaviour performance in nonanemic iron deficient infants. Pediatrics, 71,877-880. 7. Lozoff, B., Brittenham, G. M., Wolf, A. W. et al. (1987). Iron deficiency anemia and iron therapy effects on infant development test performance. Pediatrics, 79,981-995. 8. Walter, T,, De Andrea, I., Chadud, P. & Perales, C. G. (1989). Iron deficiency anemia: adverse effects on infant psychomotor development. Pediatrics, 84, 7-17. 9. Behrman, R. & Vaughan, V. (1987). Nelson Textbook of Pediatrics, 13th edn. Philadelphia: Saunders. 10. Dallman, P. R., Yip, R. & Johnson, C. (1984). Prevalence and causes of anemia in the United States, 1976-1980. American Journal of Clinical Nutrition, 39,437-445. 11. Yip, R., Walsh, K. M., Goldfarb, M. G. & Benkin, N. J. (1987). Declining prevalence of anemia in childhood in a middle-class setting: a pediatric success story? Pediatrics, 80, 330-334. 12. Yip, R., Benkin, N. J., Fleshood, L. & Trowbridge, F. L. (1987). Declining prevalence of anemia among low income children in the United States. Journal of the American Medical Association, 258, 1619-1623. 13. Lisikoff, P. (1989). The long term impact and feasibility of a program aimed at the control and prevention of iron deficiency anemia in infants. Beit Shemesh 1987. MPH thesis, Hebrew University-Hadassah School of Public Health, Jerusalem. 14. Kark, S. L, (1981), Community Oriented Primary Care. New York: Appleton Century Crofts, Chapter 6. 15. Kark, S. L., Peritz, E., Shiloh, A. & Slome, C. (1964). Epidemiology analysis of the hemoglobin picture in parturient women in Jerusalem. American Journal of Public Health, S4,947-960. 16. Palti, H., Valderama, C., Pogrund, R. et aI. (1988). Evaluation of the effectiveness of a structured breast feeding promotion program integrated into a maternal and child health service in Jerusalem. Israel Journal of Medical Sciences, 24,342-348. 17. SPSS Inc. (1983) Statistical Package for the Social Sciences (SPSSX). User's guide. New York: McGraw Hill. 18. Paki, H., Adler, B. & Wolf, N. (1977). An epidemiological study of haemoglobin levels in infancy in Jerusalem. Acta Paediatrica Scandinavica, 66,513-517. 19. Palti, H., Adler, B. & Rcshef, A. (1977). A semilongitudinal study of food intake, anemia rate and body measurements of 6 to 24 months old children in a Jerusalem community. American Journal of Clinical Nutrition, 30,268-274. 20. Lundstrom, V., Slimes, M. A. & Dallman, P. R. (1977). At what age does iron supplementation become necessary in low birth weight infants? Journal of Pediatrics, 91, 878-883.