Early-life risk factors for adult chronic disease: follow-up of a cohort born during 1964-1978 in an urban slum of Lahore, Pakistan.

Evidence suggests that risk of chronic diseases may be programmed during the foetal and early life of the infant. With high rates of low birthweight coupled with a rapid nutritional transition, low-income countries are facing an epidemic of chronic diseases. Follow-up of a cohort of adults born during 1964-1978 in an urban slum in Lahore, Pakistan, is presented in this paper. In 695 of these adults (mean age=29.0 years, males=56%), blood pressure, fasting blood glucose, and body mass index (BMI) were measured to assess early-life predictors of risk of chronic diseases. Sixteen percent of the study population was born with a low birthweight (<2,500 g). A significant positive association (p=0.007) was observed between birthweight and BMI; additionally, adjusting for age and gender, the association with BMI was highly significant (p=0.000). Conversely, a significant negative association (p=0.016) was observed between birthweight and adult levels of fasting plasma glucose; after adjustment for age and gender, the association was more significant (p=0.005) No association was observed between birthweight and adult blood pressure. The results suggest that low birthweight may increase later risk of impaired glucose tolerance in urban Pakistani adults. Further research in this area is warranted.

Revaccination does not improve an observed deficit in antibody responses in Pakistani adults born of a lower birth weight.

We have previously shown that the generation of antibodies to a polysaccharide vaccine (Typhim Vi) is compromised in Pakistani adults born of a lower birth weight. To assess whether this represents a true B-cell-dependent deficit, we revaccinated subjects with a second dose of the same vaccine and with a polysaccharide-protein conjugate vaccine to a different polysaccharide antigen (conjugated Haemophilus influenzae type b (Hib) vaccine). Anti-Vi IgG levels remained positively correlated with birth weight (p=0.0284) but no associations were observed between anti-Hib IgG levels and size at birth. These findings indicate that small size at birth results in a poor antibody response to vaccination with a polysaccharide antigen vaccine in adulthood, even following a second dose of the vaccine. No such association was observed in response to a polysaccharide-protein conjugate vaccine indicating an early-life programming effect on the generation of antibodies during a B-cell-dependent immune response.

Effect of month of vaccine administration on antibody responses in The Gambia and Pakistan.

OBJECTIVE: To explore the relationship between calendar month of administration and antibody (Ab) response to vaccination in subjects from The Gambia and Pakistan, two countries with distinct patterns of seasonality. METHODS: Three cohorts were investigated: Responses to rabies and pneumococcal vaccine were assessed in 472 children (mean age 8 years, males 53%) from rural Gambia. Responses to tetanus, diphtheria and hepatitis B (HBsAg) were investigated in 138 infants also from The Gambia (birth to 52 weeks of age, males 54%). Responses to rabies and Vi typhoid vaccines were assessed in 257 adults from Lahore, Pakistan (mean age 29.4 years, males 57%). RESULTS: In Gambian children, significant associations were observed between month of vaccination and Ab response for the pneumococcal and rabies vaccines. As no consistent pattern by month was observed between the responses, it is assumed that different immunomodulatory stimuli or mechanisms were involved. In Pakistani adults, a significant pattern by month of vaccination was observed with both rabies and typhoid vaccine. No monthly influences were observed in the infant study to the tetanus, diphtheria or the HbsAg vaccines. CONCLUSIONS: Antibody responses to certain specific vaccines are influenced by month of administration. Further research is required to elucidate the precise mechanisms explaining these observations, but a co-stimulatory effect of seasonally variable environmental antigens is a likely cause. Future studies of Ab response to vaccination in countries with a seasonally dependent environment should consider month of vaccination when interpreting study findings.

Perinatal health in Pakistan: a review of the current situation.

UNLABELLED: The perinatal mortality rate of 63-92/1000 births as reported from two provinces of Pakistan is unacceptably high. A vast majority of births and neonatal deaths occur at home and remain unregistered. In spite of a number of child survival programmes of proven efficacy in place, the impact on perinatal health is poor. CONCLUSION: Initiatives such as behaviour change communication, skill-based training of birth attendants and reaching the un-reached may be the key future strategies to reduce perinatal losses.

Birth weight predicts response to vaccination in adults born in an urban slum in Lahore, Pakistan.

BACKGROUND: Substantial evidence exists linking small size at birth to later-life susceptibility to chronic disease. Evidence is also emerging that some components of immune function may be programmed in early life. However, this evidence is limited and requires confirmation. OBJECTIVE: We investigated the association between size at birth and response to vaccination in a cohort of 257 adults (mean age: 29.4 y; 146 men) born in an urban slum in Lahore, Pakistan, during 1964-1978. DESIGN: A single dose of Vi polysaccharide vaccine for Salmonella typhi and 2 doses of rabies vaccine were given to each subject. Antibody titers were measured in prevaccination serum samples (Vi) and in postvaccination samples (Vi and rabies). RESULTS: The mean birth weight of the subjects was 3.24 kg; 14% of the subjects had low birth weights (<2.5 kg). Vaccine responses were not consistently associated with contemporary variables (month of study, sex, current age, or indicators of wealth). Response to typhoid vaccination was positively related to birth weight (anti-Vi immunoglobulin G: r = 0.138, P = 0.031; anti-Vi immunoglobulin M: r = 0.197, P = 0.034). Response to the rabies vaccine was not significantly associated with birth weight. CONCLUSIONS: These findings add to a growing body of evidence suggesting that components of the immune system may be permanently programmed by events in early life. The contrasting effects on typhoid and rabies responses suggest that antibody generation to polysaccharide antigens, which have greater B cell involvement, is compromised by fetal growth retardation.