Bridging social and biological scienceswww.ucl.ac.uk/icls

Noriko Cable, Mel Bartley, Anne McMunn, Yvonne Kelly

University College London

SLLS 2010, Cambridge

SLLS 2010 www.ucl.ac.uk/icls

An ESRC Research Centre

Gender differences in the effect of breast feeding on adult psychological well-being

Source: WHO

SLLS 2010 www.ucl.ac.uk/icls

An ESRC Research Centre

Background• WHO and UNICEF recommend exclusive

breastfeeding for 6months.

• Established links between breastfeeding and physical health, extending to adulthood

• What about psychological health?

• Beyond childhood?

SLLS 2010 www.ucl.ac.uk/icls

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The theoretical model:

Breastfeeding Childhood psychosocial adjustment

Adult psychological ill health

Adult self-efficacy

SLLS 2010 www.ucl.ac.uk/icls

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Aims:

• To examine the role of breastfeeding on– childhood psychosocial adjustment– adulthood psychological well-being

• To compare the results are persistent between two British Birth Cohort Studies born 12 years apart

SLLS 2010 www.ucl.ac.uk/icls

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Method:

• Participants:– NCDS (1958 cohort)

• Birth, age 7, age 11, age 33• Men (N=3,797); Women (N=3,953)

– BCS70 (1970 cohort)• Birth, age 5, age10, age30• Men (N=3,166); Women (N=3,326)

SLLS 2010 www.ucl.ac.uk/icls

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Methods:

• Independent variables:– Breastfeeding

• 1 month+(=1), Never/less 1 mo (=0)

SLLS 2010 www.ucl.ac.uk/icls

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Methods:

• Outcome variables:– Childhood psychosocial adjustment (2pt, top three

quartiles =1, being adjusted)• NCDS: Teacher assessed BSAG score• BCS70: Teacher assessed Rutter score

– Adult psychological well-being• Psychological health

– Malaise score 0-6 (=1, healthy), 7+ (=0, ill health)

• Self-efficacy– Cut off a total sum (3 items) into a 2pt (0=low, 1= high self-

efficacy

SLLS 2010 www.ucl.ac.uk/icls

An ESRC Research Centre

Methods:

• Confounders– Socio-demographic adversity index (0, not

disadvantaged, 1=disadvantaged)• Cut off at a median of the sum of:

– Maternal education» Stayed in min. education=0, No=1

– Mother’s age» Non-teen =0, teenage=1

– Parenthood » two parents=0, lone parent =1)

– Being a first born child» no siblings =0, has siblings=1 indicated by parity

SLLS 2010 www.ucl.ac.uk/icls

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Analysis:

• Logistic regression – Childhood psychosocial adjustment– Adult psychological well-being

• Compared the results by gender and cohorts

SLLS 2010 www.ucl.ac.uk/icls

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Findings:

– Proportions of breastfeeding 1mo+ decreased• 20% Mothers of BCS70 children breastfed for 1+

months

– Most of the participants psychologically well childhood & adulthood

– Breastfeeding practice appears to associate with social adversity

SLLS 2010 www.ucl.ac.uk/icls

An ESRC Research Centre

Findings: descriptive by cohort (Men)

0

10

20

30

40

50

60

disadvantaged+ maladjusted+ psychologically ill health+ low self-efficacy

NCDS: Never/less

NCDS: 1mo+

BCS70:Never/less

BCS70:1mo+

%

SLLS 2010 www.ucl.ac.uk/icls

An ESRC Research Centre

Findings: descriptive by cohort (Women)

0

10

20

30

40

50

60

disadvantaged+ maladjusted+ psychologically ill health+ low self-efficacy

NCDS: Never/less

NCDS: 1mo+

BCS70:Never/less

BCS70:1mo+

%

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Findings: Childhood psychosocial adjustment

Unadjusted Adjusted*

Boys NCDS 1.17(1.01-1.36) 1.11(0.96-1.29)

BCS70 1.18(0.96-1.45) 1.14(0.93-1.41)

Girls NCDS 1.30(1.10-1.55) 1.25(1.05-1.48)

BCS70 1.55(1.23-1.94) 1.44(1.15-1.81)

Note: adjusted for social demographic adversity

SLLS 2010 www.ucl.ac.uk/icls

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Findings:

• Girls appear to benefit from being breastfed more than 1 month.

• All effects were adjusted for social adversity

SLLS 2010 www.ucl.ac.uk/icls

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Findings: Adult psychological health

Unadjusted Adjusted*

Men NCDS 1.03(0.78-1.37) 0.97(0.73-1.29)

BCS70 1.12(0.87-1.44) 1.04(0.80-1.35)

Women NCDS 1.26(1.03-1.54) 1.17(0.95-1.44)

BCS70 1.41(1.13-1.76) 1.31(1.04-1.64)

Note: adjusted for social demographic adversity+childhood psychosocial adjustment

SLLS 2010 www.ucl.ac.uk/icls

An ESRC Research Centre

Findings: Adult self-efficacy

Unadjusted Adjusted*

Men NCDS 1.15(0.99-1.33) 1.09(0.94-1.25)

BCS70 1.15(0.94-1.40) 1.06(0.97-1.30)

Women NCDS 1.16(1.01-1.34) 1.09(0.94-1.26)

BCS70 1.44(1.17-1.78) 1.31(1.06-1.61)

Note: adjusted for social demographic adversity+childhood psychosocial adjustment

SLLS 2010 www.ucl.ac.uk/icls

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Findings:• A direct path from breastfeeding to childhood

psychosocial adjustment– Supported among girls only

• A direct path from breastfeeding to adult psychological well-being (psychological health and self-efficacy)– Supported among women from BCS70 only.

• All effects were adjusted for social demographic factors and childhood psychosocial adjustment.

• Breastfeeding had no significant effects on men’s outcomes.

SLLS 2010 www.ucl.ac.uk/icls

An ESRC Research Centre

Discussion:

– Gender differences in the findings, why girls/women?• As a proxy for a mother-child relationship/attachment?• Why not so important for boys after their infanthood?• Why becomes so important to mid-childhood girls and adult

women? – Can compare with the data from the MCS

– Cohort effect, why BCS70?– Period changes in the contexts of social demographic factors? – Can compare with the data from the MCS

SLLS 2010 www.ucl.ac.uk/icls

An ESRC Research Centre

Discussion:

• Limitations– Breastfeeding measures

• Not robust enough to assess dose-response relationships with the outcomes

– Maternal education• Not precise• Social context of education• Stayed in minimum age full time education or not

SLLS 2010 www.ucl.ac.uk/icls

An ESRC Research Centre

Summary:

• The effect of breastfeeding on psychological health is limited– Not extensive as seen in physical health– Prevalent in women from the late cohort

• A path from breastfeeding to adult psychological well-being via child psychosocial adjustment

SLLS 2010 www.ucl.ac.uk/icls

An ESRC Research Centre

Summary• A direct path from breastfeeding to adult

psychological well-being for the later cohort– For NCDS women

• A direct effect from childhood psychosocial adjustment via breastfeeding

– Breastfeeding can be women’s psychological well-being across lifecourse

• Policy implications– Encourage expecting mothers to take on and continue

breastfeeding up to 6 months as recommended

SLLS 2010 www.ucl.ac.uk/icls

An ESRC Research Centre

Acknowledgement: ESRC, UK data archive and CLS

Thank you for listening!

Contact: n.cable@ucl.ac.uk

SLLS 2010 www.ucl.ac.uk/icls

An ESRC Research Centre

Descriptive: Men

0

50

100

NCDS BF <1mo BCS70 BF <1mo

mother teen

non teen

mother left f/teducationmother stayed

lone mother

two parenthouseholdSibling+

Sibling -

%

SLLS 2010 www.ucl.ac.uk/icls

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Descriptive: Women

0

50

100

NCDS BF <1mo BCS70 BF <1mo

mother teen

non teen

mother left f/teducationmother stayed

lone mother

two parenthouseholdSibling+

Sibling -

%