Michiel Van den Hof Dalhousie University Halifax, Nova Scotia.

Folic acid supplementation and fortification in Nova Scotia

Michiel Van den HofDalhousie UniversityHalifax, Nova Scotia

History of Folate History of Folate ResearchResearch

1976-1991 - Numerous small studies suggesting benefit of folic acid supplementation

1991- “Landmark” paper on benefit of folic acid supplementation to reduce the

recurrence of NTDs*

* MRC Vitamin Study Research Group: Lancet 1991


1992 -Research shows that folic acid supplementation reduces open NTDs in low-risk women*

*Czeizel AE, Dudas I: N Engl J Med 1992


1991 - 1994

- Canadian recommendations about folic acid supplementation issued:

- Health Canada

- SOGC

- Canadian Task Force on the Periodic Health Examination

Incidence of ONTD’S per 1000 Incidence of ONTD’S per 1000 births in Nova Scotiabirths in Nova Scotia

1.5 1.411.2

1.06

0.46

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1991 1992 1993 1994 1995

Livebirths/stillbirths

Total Incidence of ONTD’S per 1000 Total Incidence of ONTD’S per 1000 PregnanciesPregnancies

1.5

1.01

1.41

1.08

1.2

1.37

1.06

1.59

0.46

1.65

0

0.5

1

1.5

2

2.5

3

1991 1992 1993 1994 1995

Pregnancyterminations

Livebirths/stillbirths

2.51 2.49 2.57 2.65

2.11


1993 - 1999

- < 45% of pregnant women taking folic acid before conception


March 1996

- US-FDA orders all enriched grain products to be fortified (.14/100gm) starting January 1, 1998


November 1, 1998

- Health Canada endorses similar fortification

Questions?Questions?

Did recommendations for folic acid supplementation work?

Did the “small” amount of fortification work?

Folic Acid Folic Acid Supplementation/FortificationSupplementation/Fortification

Methods:

Nova Scotia Perinatal Database

plus

Nova Scotia Fetal Anomaly Database

combined have information on all births and birth defects that occur in this province.


Open neural tube defects:

- spina bifida

- anencephaly

- other


Pre-supplementation 1991-1994

Post-supplementation

but pre-fortification 1994-1997

Pre-fortification 1991-1997

Post-fortification 1998-2000

Folic Acid Folic Acid Supplementation/FortificatSupplementation/Fortificat

ionion

Risks for Folic Acid Fortification:

Delay diagnosis of vitamin B12 deficiency which may result in neurologic effects.

Folic Acid Folic Acid Supplementation/FortificatioSupplementation/Fortificatio

nn Spina Total

Anencephaly* Bifida** NTDs***

Pre-supplementation 1.00 1.44 2.55

1991-1994

Post-supplementation .82 1.60 2.61

Pre-fortification 1995-1997

*RR0.82,95%CI 0.51-1.32; p=0.49

**RR1.11,95%CI 0.79-1.60; p=0.64

***RR1.02,95%CI 0.77-1.35; p=0.87

Incidence of ONTD’S per 1000 Incidence of ONTD’S per 1000 PregnanciesPregnancies

1.3

1.25

0.82

1.79

0

0.5

1

1.5

2

2.5

3

1991-1994 1995-1997


Livebirths/ stillbirths

2.552.61


Spina Total

Anencephaly* Bifida** NTDs***

Pre-fortification .93 1.52 2.58

1991-1997

Post-fortification .38 .62 1.17

* RR 0.41, 95% CI 0.22-0.77; p=0.004

** RR 0.40, 95% CI 0.25-0.67; p<0.001

***RR 0.46, 95% CI 0.32-0.66; p<0.001

Incidence of ONTD’S per 1000 Incidence of ONTD’S per 1000 PregnanciesPregnancies

1.1

1.47

0.29

0.87

0

0.5

1

1.5

2

2.5

3

1991-1997 1998-2002


Livebirths/ stillbirths

1.16

2.57


With the introduction of folic acid fortification, there was a 59% reduction in anencephaly

59% reduction in spina bifida

and a 54% reduction in all NTDs.

Calculated reduction ~ 20%


Can prevention be further reduced?

Chinese study suggested ~ .6/1000 in both high and low-risk population.

Thus, further reduction may be possible,

1.0 .6 (40%).

Incidence of Anencephaly and Spina Bifida per Incidence of Anencephaly and Spina Bifida per 1000 Pregnancies in Nova Scotia1000 Pregnancies in Nova Scotia

1.44

1

0.11

1.6

0.82

0.19

0.56

0.460.15

0

0.5

1

1.5

2

2.5

3

1991-1994 1995-1997 1998-2002

OtherAnencephalySpina bifida

Michiel Van den Hof Dalhousie University Halifax, Nova Scotia.

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