What is ‘Ethnicity’?• ‘Ethnicity’ relates to factors such as culture, ancestry, language and beliefs• Different from ‘Race’, which refers to:• Physical characteristics associated with distinct populations identified by heritable phenotype or geographic ancestry
Race/ethnicity mismatch hypothesis• Nutrition and environment (‘ethnicity’) have a major influence on racial evolution• Changes in ethnicity can disadvantage some racial groups• E.g. Latino immigrants into the USA develop very high rates of obesity* * Williams JE et al, Ethn Dis 2011;21:467-72
NorthWest Thames Obstetric Database 1988-2000• 17 maternity units• On-line validation of data entry• 501,823 births• Perinatal deaths crosschecked with the Office of National Statistics
White European 362,630Black African 17,095Black Caribbean 14,557South Asian 66,409
14 12 10Perinatal 8mortality 6 4 2 0 White Black Black South European African Caribbean Asian
Black Caribbean Black African South Asian White EuropeanAffluent Poor
White EuropeanBlack Caribbean Black African South Asian
Some genetic conditions vary substantially between races• Sickle disease West Africans• β thalassaemia Eastern Mediterraneans• Cystic fibrosis Anglo-Saxons• Haemochromatosis Celts
Have the various races evolved other important genetic differences in relation to childbirth?
Gestational length distribution is different 44 42 40 38 Gestation (weeks) 36 34 32 30 28 26 24 0 20 10 40 30Patel RR, Steer PJ, Doyle P, Little M, Elliott P. 2004 Int J Epidemiol;33:107-113 Frequency (%)
Gestational length distribution is different 40 Whites 30 Frequency (%) 20 10 0 24 26 28 30 32 34 36 38 40 42 44 Gestation (weeks)Patel RR, Steer PJ, Doyle P, Little M, Elliott P. 2004 Int J Epidemiol;33:107-113
Gestational length distribution is different 40 Whites 30 Frequency (%) South Asians & 20 Blacks 10 0 24 26 28 30 32 34 36 38 40 42 44 Gestation (weeks)Patel RR, Steer PJ, Doyle P, Little M, Elliott P. 2004 Int J Epidemiol;33:107-113
Earlier maturation of the lungs in fetuses of black African origin• Farrell PM,.Wood RE. Epidemiology of hyaline membrane disease in the United States: analysis of national mortality statistics. Ped 1976;58:167-76.• Buehler JW, Strauss LT, Hogue CJ, Smith JC. Birth weight-specific causes of infant mortality, United States, 1980. Public Health Reports 1987;102:162-71.• Coulter JB. The incidence of the respiratory distress syndrome: with particular reference to developing countries. Tropical & Geographical Medicine 1980;32:277-85.• Richardson DK,.Torday JS. Racial differences in predictive value of the lecithin/sphingomyelin ratio. Am J Obstet Gynecol 1994;170:1273-8.• Robillard PY, Hulsey TC, Alexander GR, Sergent MP, de Caunes F, Papiernik E. Hyaline membrane disease in black newborns: does fetal lung maturation occur earlier? Europ J Obstet Gynecol Reprod Biol 1994;55:157-61.• Berman S, Richardson DK, Cohen AP, Pursley DM, Lieberman E. Relationship of race and severity of neonatal illness. Am J Obstet Gynecol 2001;184:668-72.
Proportion of babies transferred to Special Care +/- SE 1.2 1.0 0.8 0.6 0.4 Black African White European 0.2 0.0 24 26 28 30 32 34 36 38 40 42 44 Weeks gestation at birth P. Steer. Prematurity or immaturity? BJOG. 2006;113 Suppl 3:136-138
Proportion with meconium stained amniotic fluid +/- SE 0.5 0.4 Black African White European 0.3 0.2 0.1 0.0 26 28 30 32 34 36 38 40 42 44 Weeks gestation at birth P. Steer. Prematurity or immaturity? BJOG. 2006;113 Suppl 3:136-138
I Balchin, J. C. Whittaker, R. R. Patel, R. F. Lamont, and P. J. Steer.Racial variation in the association between gestational age and perinatal mortality: prospective study. BMJ, 2007.
Gestation specific transient tachypnoea of thenewborn/respiratory distress syndrome in infants who had planned Cesarean delivery White European Timing of planned Cesarean South Asian Delivery by Racial Group Imelda Balchin, JC Whittaker, RF Lamont, PJ Steer Obstet Gynecol 2008; White European 111:659–66 Black
Page 29Research is needed into racialdifferences in the UK to identify thepossible differences in thedistribution of perinatal risk specific togestational weeks and possiblebenefits of intervention before 41weeks.
Africans have a narrower pelvis• Narrower pelvis aids stability when running• Lumbar lordosis/ high assimilation improves backward thrust• Heavier bones mean fewer stress fractures• (less need for HRT)
Obstructed labor injury complex: obstetric fistula formation and the muti-faceted morbidity of maternal birth trauma in the developing world Arrowsmith, S., Hamlin, E.C., Wall, LL. 1996 Obstetrical and Gynecological Survey 51: 568 - 574 New cases of obstetric fistula up to 500,000 per year worldwide
More than 2 million African women sufferfrom untreated obstetric fistula (vesicovaginal or rectovaginal), a condition that is a consequence of untreated obstructed labor There is a backlog of almost 1,000,000 untreated cases in Northern Nigeria aloneF. Donnay and L. Weil.Obstetric fistula:the international response.Lancet 363 (9402):71-72, 2004.
VESICO-VAGINAL FISTULA REPAIR In Kano, Northern Nigeria Dr Kees Waaldijk. In 1995 he performed 1,184 VVF repairs as part of theNational Task Force of Nigeria. From ORGYN 1 1997 (Organon International)
Caesarean section rates in London, 1998 (81,019 births, 67,110 with ethnicity data) 30 25 20 Elective % 15 Emergency % 10 5 0 an Pa ite r e i r hi n n n an th the Ca the es ia a ea es di h ic st As B hin W ib O O In r ad ki Af rr k er C gl c k la an cla O B ckB la B
White European Black African Black Caribbean South AsianBalchin I, Steer PJ Early Hum Development (2007) 83, 749-754
White EuropeanBlack AfricanSouth AsianBlack Caribbean
An important influence onbirthweight is gestational diabetes
Study numbersRacial group Non-GDM GDMWhite European 130,325 876Black African 4,840 87Black Caribbean 4,648 50South Asian 19,685 401
White Europeans Blacks South Asians Birthweight Z score is higher in GDM only if the mother’s BMI is increased
The diabetic pregnancy and offspring BMI in childhood: a systematic review and meta-analysis• Maternal diabetes is associated with increased offspring BMI z score• This is no longer apparent after adjustment for maternal pre-pregnancy BMIPhilipps LH, Santhakumaran S, Gale C, Prior E, Logan KM, Hyde MJ, Modi N. Diabetologia. 2011 Aug;54(8):1957-66. Epub 2011 May 31.
Conclusions• Both racial origin and ethnicity affect obstetric performance• This has important implications for:• Monitoring fetal growth• Timing of delivery• Intrapartum care
Intrauterine Factors, adiposity and hyperinsulinaemia Prentice, A. BMJ 2003;327:880-1
Persistence of lower birthweight in second generationSouth Asian babies born in the United KingdomMargetts BM, et al, J Epidemiol Community Health 2002;56:684-687
Birthweight centile charts for South Asian Infants born in the UKSeaton SE et al, Neonatology 2011;100:398-403
Genetic influence (ONS data 1975-2000)Georgina Ronalds Dave Leon N = 4149 136 190 121307
Consensus statement for diagnosis of obesity, abdominal obesity and the metabolic syndrome for Asian IndiansAsian Indians exhibit unique features of obesity;•excess body fat,•abdominal adiposity,•increased subcutaneous and intra-abdominal fat,•deposition of fat in ectopic sites (liver, muscle, etc.).Obesity is a major driver for the widely prevalentmetabolic syndrome and type 2 diabetes mellitus (T2DM)in Asian Indians in India and those residing in other countries.Based on percentage body fat and morbidity data,limits of normal BMI are narrower and lower in Asian Indiansthan in white Caucasians.Misra A, et al. J Assoc Physicians India. 2009 Feb;57:163-70
Obesity-related non-communicable diseases: South Asians vs White Caucasians • South Asians are at higher risk than White Caucasians for the development of obesity and obesity-related non-communicable diseases • Determinants include: – high body fat, high truncal, subcutaneous and intra-abdominal fat, and low muscle mass – hyperinsulinemia, hyperglycemia, dyslipidemia, hyperleptinemia, low levels of adiponectin and high levels of C-reactive protein, procoagulant state and endothelial dysfunction • Lower cut-offs for obesity and abdominal obesity have been advocated for Asian Indians – BMI; overweight >23 to 24.9 kg m(-2) – obesity ≥ 25 kg m(-2); – WC; men ≥ 90 cm and women ≥ 80 cm, respectivelyMisra A, Khurana L. Int J Obes (Lond). 2011 Feb;35(2):167-87. Epub 2010 Jul 20.
The thin-fat phenotype and global metabolic disease risk• The thin-fat phenotype occurs when fat is added to an already thin frame• The thin-fat phenotype may be programmed during fetal growth• the weight of evidence appears to link the thin-fat phenotype to an environmental and lifestyle phenomenon occurring in previously thin people• This is particularly relevant in India, given the pace of transition over the last two decades Kurpad AV, Varadharajan KS, Aeberli I. Curr Opin Clin Nutr Metab Care. 2011 Nov;14(6):542-7.
The influence of maternal body massindex on infant adiposity and hepatic lipid content• Infant abdominal AT and liver lipid increase with increasing maternal BMI across the normal range.• These effects may be the initiating determinants of a life-long trajectory leading to adverse metabolic health Modi N et al, Pediatr Res. 2011 Sep;70(3):287-91.
Whole body magnetic resonance imaging of healthy newborn infants demonstrates increased central adiposity in Asian Indians• Abdominal adiposity and metabolic ill health in Asian Indians are a growing public health concern• Although smaller in weight, head circumference, and length, the Asian Indian neonates had significantly greater absolute adiposity in all three abdominal compartments in comparison to the white European babies despite similar whole body adipose tissue content• Preventive measures must involve maternal health, intrauterine life, and infancy Modi N, Thomas EL, Uthaya SN, Umranikar S, Bell JD, Yajnik C Pediatr Res. 2009 May;65(5):584-7.
CONCLUSIONS• Maternal age and BMI are important risk factors for GDM• Maternal age is more important in Black Africans and South Asians than in White Europeans• BMI is particularly important in South Asians, especially in relation to birthweight• Strategies to reduce the incidence of GDM and type 2 diabetes will need to target preconception counselling, maternity care, and infant feeding