When Children Become Adults: Methodological Challenges for International Birth Cohort Studies: The Cebu Longitudinal Health and Nutrition Survey Linda Adair, PhD University of North Carolina at Chapel Hill

The Cebu Longitudinal Health and Nutrition Survey (CLHNS) Historical Context Goal: A multipurpose demographic survey to assess determinants and consequences of maternal and child nutrition and health Early 1980s concern with how infant feeding affected child morbidity and growth Why Cebu? Availability of population institute with capacity to launch large, longitudinal study Heterogeneity of infant feeding in urban and rural communities Support of the Mayor of Cebu

CLHNS design was based on the Mosley & Chen Health Determinants model HEALTH OUTCOME (growth, mortality) PROXIMATE (nutrition, infection) UNDERLYING (SES, environment)

The CLHNS population included residents of 17 urban and 16 rural barangays of Metro Cebu Philippines Cebu Province Metro Cebu

Diverse urban, mountainous, and island communities Metro Cebu: Diverse urban, mountainous, and island communities

Sample Baseline (1983-4) All pregnant women in 33 randomly selected communities invited to participate Data collected at 30 weeks gestation (N=3,327), then during multiple follow-up surveys 3,080 single live births form the one year birth cohort

Follow-up Surveys Year N Age (yr) 1984 3080 1986 2462 2 1991 2264 8.5 1986 2462 2 1991 2264 8.5 1994 2186 11.5 1998 2089 15.5 2002 2023 19 2005 1888 21-22 2007 1817 23-24 2009 1709 25-26

Multilevel data collection: Individual, Household and Community Health Anthropometry Diet Activity IQ Schooling Work Environment Income, assets

Dual Focus on CLHNS mothers and birth cohort of offspring Enables study of health profiles across large segments of the lifecourse Moms: age 15-45 yr at baseline 15-45 yr: beginning to end of reproductive years 45+: post reproductive years Index child (IC): birth to young adulthood

1998 and 2005 Biomarkers Blood pressure Fasting blood samples Glucose, insulin, adiponectin Plasma lipids Inflammatory/immune markers DNA extracted, analyzed with Metabochip

Socioeconomic Trends in the Philippines Cebu: fastest growth area in the Philippines Increased GNP and per capita income High ownership of TVs, phones High rates of secondary school completion and college education compared with most other low income Asian countries (esp. among women) High degree of urbanization

Pregnancies occurred in context of high maternal undernutrition Offspring grew up in an increasingly obesogenic environment

Infant and young child outcomes At Birth 11.5% LBW (<2.5 kg) 12.9% Preterm (<37 weeks gestation) ~23% Small for Gestational Age Age in months

Schooling status of CLHNS young adults at age 21 years Not Enrolled Still Enrolled (18%)

In a sample where 23% of infants were born SGA, CVD risk factors have become prevalent:

Challenges: Funding and age-relevant focus over the lifecourse Child life phase Mothers Offspring Funding Gestation & birth Pregnancy complications, maternal mortality LBW, preterm birth, neonatal mortality NICHD, Nestle, Wyeth International,Ford Infancy Maternal depletion, birth spacing Growth faltering, morbidity, (diarrhea, respiratory), mortality Childhood Cognitive development, poor school attainment Thrasher, NNI, World Bank Adolescence Emergence of CMD risk Sexual health, early pregnancy USAID Mellon Adulthood CMD risk, aging NHLBI, NIA

Challenges: Attrition Loss to follow-up owing to: Child death Migration away from Metro Cebu Refusal Ineligibility Major reasons for losses vary with age

CLHNS sample ICs 93 52 58 87 120 104 134 birth 3,080 1 yr 2600 85 302   In survey Died Migrated Refused/ ineligible birth 3,080 1 yr 2600 85 302 93 2 yr 2462 144 381 1991 2264 209 555 52 1994 2186 217 619 58 1998 2089 695 87 2002 2023 226 744 2005 1888 234 838 120 2007 1817 245 914 104 2009 1709 250 987 134

Migrants Destinations Moms IC’s Number (Percent) Moms (through 2012) Within Cebu Province 305 (29.9%) 270 (27.4%) Outside Cebu Province 381 (37.1%) 377 (38.2%) Metro Manila 142 (13.8%) 154 (15.6%) Outside Philippines 67 (6.5%) 13.5%) Unknown 131 (12.8%) 53 (5.4%) Total 1026 987

Mortality: Offspring

Challenges: Survey Logistics In the original survey, respondents lived in 33 barangays, while in the latest survey, they lived in 176 different barangays. More travel, fewer clustered interviews, more community surveys Respondents are more likely to be working, so flexible hours (evenings and weekends) are needed for interviews Traffic, crime Travel time and safety for field staff

Challenges: changing questionnaires and measurement methods Best indicators of SES have changed over time Survey of household assets must include more “modern” items such as cell phones, internet, modern appliances Relevant questions/behaviors/measurements change with age e.g. physical activity for infants, children and adolescents (in school) and young adults (working) e.g. maturation assessments e.g. risky behaviors

Challenges: changing questionnaires and measurement methods Diet assessment: 1st 2 yrs: single 24 hour dietary recalls every 2 months Age 8: FFQ Ages 11-adulthood: multiple 24 hr recalls Blood pressure measurement Mercury sphygmomanometers Automated devices

CLHNS Major Contributions Determinants and consequences of infant feeding, esp. importance of exclusive BF Early life factors related to IQ, school performance and educational attainment Emergence of chronic disease risk in relation to early life factors and current urbanization and lifestyle changes Collaborations with other research groups: COHORTS Genetics consortia