Exposure to second hand smoke at home and its associated factors findings from the global adult tobacco use survey in vietnam, 2010 (2)

Cancer Causes Control (2012) 23:99–107
DOI 10.1007/s10552-012-9907-z

ORIGINAL PAPER

Exposure to second-hand smoke at home and its associated
factors: findings from the Global Adult Tobacco Use survey
in Vietnam, 2010
Hoang Van Minh • Kim Bao Giang • Le Thi Thanh Xuan •
Pham Thi Quynh Nga • Phan Thi Hai • Nguyen Thac Minh
Nguyen The Quan • Jason Hsia

•

Received: 5 September 2011 / Accepted: 27 January 2012 / Published online: 29 February 2012
Ó Springer Science+Business Media B.V. 2012

Abstract
Objective The paper describes the pattern of exposure to
second-hand smoke (SHS) at home among the adult population of Vietnam and examines associated socio-demographic factors.
Methods A total of 11,142 households were selected for
this survey using a two-phase sampling design analogous
with three-stage stratified cluster sampling. The dependent
variable was the status of exposure to SHS at home.
Independent variables included gender, age, occupation,
asset-based wealth quintile, ethnicity, marital status, residence. Logistic regression modelling was performed to
examine the association with relevant factors of patterns of
exposure to second-hand smoke among non-smokers.
Results Of adults aged 15 years and above (representing
approximately 47 million people) 73.1% reported they
were exposed to SHS at home at least monthly. Considering non-smokers only, the prevalence of exposure to

SHS at home was 67.6% (equivalent to approximately 33
H. Van Minh (&) Á K. B. Giang Á L. T. T. Xuan
Institute for Preventive Medicine and Public Health,
Hanoi Medical University, No 1- Ton That Tung, Dong Da,
Hanoi, Vietnam
e-mail:
P. T. Q. Nga
World Health Organization Office in Vietnam, Hanoi, Vietnam
P. T. Hai Á N. T. Minh
Vietnam Steering Committee on Smoking and Health
(VINACOSH), Hanoi, Vietnam
N. T. Quan
General Statistics Office, Hanoi, Vietnam
J. Hsia
Center for Disease Control and Prevention, Atlanta, GA, USA

million non-smokers). The significant correlates of the
status of exposure to SHS at home among non-smokers
were female gender, ethnic minority, low education, and
lack of smoking restriction at home.
Conclusion The study showed that a high percentage of
people are exposed to second-hand smoke at home. Disadvantaged people were more likely than the better-off to
be exposed to SHS at home.
Keywords Second-hand smoke Á Socio-demographic
factors Á Global Adult Tobacco Use survey Á Vietnam

Introduction
Second-hand smoke (SHS) exposure, also known as
‘‘involuntary smoking’’ or ‘‘passive smoking’’, is nonsmokers’ inhalation of smoke from the exhalation of
smokers or from burning cigarettes [1, 2]. Evidence of the

adverse health effects of exposure to SHS has been accumulating for nearly 50 years [3–5]. The U.S. Surgeon
General estimates that living with a smoker increases a
non-smoker’s chances of developing lung cancer by
20–30% [1]. Research also suggests that second-hand
smoke may increase the risk of breast cancer, nasal sinus
cavity cancer, and nasopharyngeal cancer in adults, and
leukemia, lymphoma, and brain tumours in children [1, 2,
6, 7]. Exposure to second-hand smoke may increase the
risk of non-cancerous conditions, for example chronic
coughing, phlegm, and wheezing, chest discomfort, severe
lower respiratory tract infections, for example bronchitis or
pneumonia, and eye and nose irritation [6, 8, 9].
Globally, it is estimated that approximately one-third of
adults are regularly exposed to second-hand tobacco
smoke [10]. Second-hand smoke is estimated to cause

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100

approximately 600,000 premature deaths per year worldwide. Of all deaths attributable to second-hand tobacco
smoke, 31% occur among children and 64% occurs among
women [10]. In addition to a large and growing health
burden, second-hand smoke exposure also imposes economic burdens on individuals and countries, both the direct
costs of health care and indirect costs from reduced productivity. Several studies estimate that 10% of total
tobacco-related economic costs are attributable to secondhand smoke exposure [11].
Although smoking prevalence is decreasing in many
high-income countries, it is increasing in many low and
middle-income countries [12]. As a result, the amount of

second-hand smoke and its associated burden of disease are
now rising in low and middle-income countries [13]. The
burden of morbidity from SHS exposure, as measured by
disability adjusted life years (DALYs), has been shown to
be higher in low-income countries in Southeast Asia and in
the eastern Mediterranean region than in Europe [13].
Disadvantaged people (especially, women and children)
have been suffering more from the burden of disease
caused by second-hand smoke [1, 13].
In Vietnam, a low-income country in Southeast Asia,
smoking is the main form of tobacco use and is very
common. The prevalence of smoking among those aged
15 years old and over in 2002 was 56.1% among men and
1.8% among women). In 2002, 63% of households had at
least one smoker. 71% of children under age 5 lived in
households with at least one smoker [14]. In 2003, nearly
60% school-attending youth reported being exposed to
second-hand smoke at home [15].
Although the amount of research on tobacco use in
Vietnam has recently increased rapidly, there remains a
lack of reporting on the pattern of exposure to second-hand
smoke among populations. The objectives of this paper are
to describe the pattern of exposure to second-hand smoke
at home among the adult population in Vietnam and to
examine its socio-economic correlates. This case study
provides scientific evidence for policy changes and intervention in Vietnam, and in other low and middle-income
countries.

Methods
Data source

Data used in this paper were obtained from the Global
Adult Tobacco Survey (GATS) conducted in Vietnam in
2010. The GATS is a household survey (using face-to-face
interviews) that was launched in February 2007 as a new
component of the ongoing Global Tobacco Surveillance
System (GTSS) [16]. The GATS in Vietnam was designed

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Cancer Causes Control (2012) 23:99–107

to be a nationally representative survey of all non-institutionalized men and women age 15 and older who considered Vietnam to be their primary place of residence.
Sample size and sampling
A two-phase sampling design analogous to three-stage
stratified cluster sampling was used. According to the
GATS sample design protocol, to obtain reliable estimates
of key variables for gender and urban/rural areas 8,000
people are required. On the basis of previous similar
national household surveys, it was assumed that overall
ineligibility and non-response would be 35%. After taking
the response into account, the final total sample size was
11,142. Half of the enumeration areas (EAs) to be sampled were then assigned to urban and half to rural.
Because of the different sizes of urban and rural areas,
GATS sampled 18 households from each urban EA and 16
households from each rural EA. Therefore a total of 657
EAs were sampled to obtain 11,142 households. The
sample size for EAs was then proportionally allocated
across six strata, on the basis of the total number of
households.
In 2009, the General Statistics Office (GSO), Vietnam,

conducted a population and housing census. The GSO also
prepared a 15% master sample to serve as a future
national survey sampling framework. The 15% master
sample contains a subset of EAs that consists of 15% of
the population in Vietnam stratified by three groups. The
first group consists of 132 districts, towns, or cities of
provinces. The second group consists of 294 plain and
coastal districts. The third group consists of 256 mountainous and island districts. The GATS sample was drawn
from the 15% master sample after further stratification of
the three groups into urban and rural areas (six strata in
total).
At the first stage of sampling, the primary sampling unit
(PSU) was an enumeration area (EA). The sampling
framework was a list of the EAs, from the 15% master
sample, with the number of households and identifiable
information, administered by the GSO, Vietnam, in 2009
from the census. For each of the six strata, the designated
number of EAs was selected. A selection probability proportional to size (PPS) sampling method was used, where
the size was the probability of selection of an EA, using
PPS sampling, from the entire target population divided by
the probability of selection of an EA for the master sample.
At the second stage of sampling, 18 households
from the selected urban EA and 16 households from the
selected rural EA were chosen using simple systematic
random sampling. One eligible household member from
each selected household was then randomly chosen for
interview.


Cancer Causes Control (2012) 23:99–107

Note that this design and the design in which EAs were
sampled directly from the universe were analogous. The
probability of selection of an eligible individual was calculated as the product the of probability of selection for
each stage. The sampling base weight for an eligible
individual was the inverse of the probability of selection
shown above.
Data collection procedure
Data collection was done by the GSO, under the cosupervision of the World Health Organization in Vietnam,
Vinacosh, and Hanoi Medical University. Twenty-six datacollection teams were involved in GATS Vietnam 2010.
Each team consisted of one team leader and four interviewers to ensure close supervision and collection of high
quality data. They had computer skills and previous
experience in conducting of GSO household-based surveys,
especially GSO health-related surveys. In addition to the
qualifications needed for interviewers, team leaders for the
GATS were experienced in using computers and handheld
(iPAQ) devices and had previous experience of working
with local authorities.
Handheld computers were used for capturing data. Each
interviewer and team leader had one iPAQ. A real case file
containing addresses and names of the households assigned
to the interviewer was preloaded into the iPAQ before the
field work. All the responses were entered by the interviewer in the iPAQ, with the help of a stylus for touching
the key-pad on the screen. Data collection was conducted
from 22 March 2010 to 13 May 2010 in all 63 provinces of
Vietnam.
Study variables
In this work, the dependent variable was the status of
exposure to SHS at home. The question in the questionnaire was ‘‘What is the frequency of tobacco smoking
inside your house (either family members or guests)?’’

Respondents who answered ‘‘daily’’ or ‘‘weekly’’ or
‘‘monthly’’ to the question were classified as people who
were exposed to SHS at home. Independent variables were
gender, age, occupation, asset-based wealth index quintile
(this index was constructed by using household assets,
utilities, and housing construction as variables in principalcomponents analysis and computing a wealth index for
each household), ethnicity, marital status, residence. We
also included variables on the availability of smoking rules
at home and at work, and beliefs of the respondent about
the dangers of tobacco smoking and the dangers of secondhand smoke (respondents who believed that breathing other
people’s smoke causes serious illness and specific disease
in non-smokers, i.e., heart disease in adults, lung illness in

101

children, lung cancer in adults, emphysema, low birth
weight, premature birth).
Data analysis
Both descriptive and analytical statistical analysis was
performed using Stata10 software (Stata Corporation). We
conducted descriptive analysis of the status of exposure to
SHS at home among non-smokers. The analytical statistics
were used for analysis of the status of exposure to SHS
among non-smokers only. Multivariate logistic regression
modelling was performed to examine the association
between patterns of exposure to second-hand smoke among
non-smokers and relevant factors. The sampling design
was fully taken into consideration in the data analysis.
Weights were used in all computations. A significance
level of 0.05 was used.

Results
Socio-demographic characteristics of the study
population
Among the 11,142 sampled households, 10,383 were
completely screened, giving a household response of
96.9%. The household response was a little higher in rural
areas than in urban areas (97.5 and 96.5%, respectively).
Overall, only 0.6% of the selected households refused to
respond to the survey. Among 10,383 individuals selected
from the completely screened households, 9,925 were
completely interviewed, so the person-level response was
95.7%. The person-level response was also a little higher in
rural areas than in urban areas (96.3 and 95.0%, respectively). Overall, only 0.6% of the selected individuals
refused to respond to the survey. In GATS Vietnam 2010,
the total response was 92.7% (93.9% in rural areas and
91.7% in urban sites) (Table 1).
Table 2 presents sample size and population estimates
by selected socio-demographic characteristics. The 9,925
completed interviews represented an estimated 64.3 million
adults age 15 and over in Vietnam. By age group, people
age 25-44 made up the largest proportion (41.9%) and
those 65 and above accounted for the smallest share
(8.8%). Most of the study population reported having lower
secondary school education (52.5%) or primary or less
education (26.0%). People with a college degree or above
made up 7.2% of the study population. The main occupation of the study population was Farmer (49.6%), followed
by Service/Sales (19.2%), and Production/Driving (12.9%).
Other occupations were Manager/Professional (6.6%);
Construction/Mining (5.2%); Office workers (2.0%); Forestry/Fishing (1.8%), and others (2.7%). By ethnicity,

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Cancer Causes Control (2012) 23:99–107

Table 1 Number and percentage of households and persons interviewed, and response by residence (unweighted)—GATS Vietnam, 2010
Residence

Total

Urban

Rural

Number

Percent

Number

Percent

Number

Percent

Completed (HC)

5,525

92.2

5,158

94.4

10,383

93.2

Completed—No one eligible (HCNE)
Incomplete (HINC)

1
5

0.0
0.1

0
9

0.0
0.0

1
14

0.0
0.1

No screening respondent (HNS)

2

0.0

5

0.0

7

0.1

Refused (HR)

55

1.0

9

0.2

64

0.6

Unoccupied (HUO)

216

3.8

166

6.5

382

3.4

Address not a dwelling (HAND)

29

0.5

18

0.2

47

0.4

Other (HO)a

137

2.4

107

0.9

244

2.1

Total households selected

5,670

100

5,472

100

11,142

100

Household response (HR) (%)b

96.5%

Selected household

97.5%

96.9%

Selected person
Completed (PC)

4,958

94.9

4,967

96.3

9,925

95.6

Incomplete (PINC)

2

0.0

4

0.1

6

0.1

Not eligible (PNE)

7

0.1

2

0.0

9

0.1

Refused (PR)

56

1.1

9

0.2

65

0.6

Incapacitated (PI)

50

1.0

44

0.9

94

0.9

Other (PO)
Total number of sampled persons

152
5,225

2.9
100

132
5,158

2.6
100

284
10,383

2.7
100

Person-level response (PR) (%)c

95.0%

96.3%

95.7%

Total response (TR) (%)d

91.7%

93.9%

92.7%

a

a

Other includes Nobody Home and any other result code not listed

b

Calculate Household response (HR) by:

HCỵHCNEị100
HCỵHCNEỵHINCỵHNSỵHRỵHO
c

Calculate Person-level response (PR) by:

PC100
PCỵPINCỵPRỵPIỵPO
d

Calculate Total response (TR) by: (HR x PR)/100

An incomplete household interview (i.e., roster could not be finished) was considered a non-respondent to the GATS. Thus, these cases (HINC)
were not included in the numerator of the household response
A completed person interview (PC) includes respondents who had completed at least question E1 and who provided valid answers to questions
B1/B2/B3. Respondents who did not meet these criteria were regarded as incomplete (PINC) non-respondents to GATS and thus, were not
included in the numerator of the person-level response

84.5% of the population were Kinh people (the majority)
and the remaining 15.5% belonged to other ethnic minority
groups. By marital status, 67.7% of the population were
married, 26.2% were still single, and the remainder (6.2%)
were separate/divorce/widow. Two-thirds of people age 15
and over in Vietnam were living in rural areas.

Prevalence of SHS at home
In Vietnam in 2010, 73.1% of adults aged 15 years and
above (representing approximately 47 million people)
reported that they were exposed to SHS at home at least

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monthly.1 Considering non-smokers only (76.2% of the
surveyed population or approximately 49 million people),
the prevalence of exposure to SHS at home was 67.6%
(equivalent to approximately 33 million non-smokers).
Table 3 shows the pattern of SHS exposure at home
among the non-smoking population in the past 30 days
according to selected socio-economic status. The prevalence of exposure to SHS at home among non-smoking
males was lower than that among non-smoking females
1
Adults reporting that smoking inside their home occurs daily,
weekly, or monthly.


Cancer Causes Control (2012) 23:99–107

103

Table 2 Distribution of study subjects by selected socio-demographic characteristics—GATS Vietnam, 2010
Characteristic

Weighted %

Sample

size

Weighted
number

Male

4,356

31,258,108

48.6

Female
Age

5,569

33,062,657

51.4

15–24

1,656

16,637,021

25.9

25–34

2,053

12,661,740

19.6

35–44

2,198

14,281,840

22.2

45–54

1,867

9,657,483

15.0

55–64

1,019

5,407,631

8.4

1,132

5,675,050

8.8

Gender

[64
Education

–

Primary

2,034

12,377,177

26.0

Secondary

3,981

25,031,220

52.5

High school

1,023

6,793,646

14.3

1,227

3,447,042

7.2

College, university
Occupation

–

Correlates of SHS at home

Manager/Professional

845,000

3,120,000

6.6

Office worker
Service/Sales

220,000
1,589,000

916,000
8,991,000

2.0
19.2

Farming

3,069,000

23,255,000

49.6

Forestry/Fishing

120,000

867,000

1.8

Construction/Mining

317,000

2,442,000

5.2

Production/Driving

834,000

6,063,000

12.9

Other

248,000

1,272,000

2.7

Ethnicity
Kinh (the majority)

8,555

54,368,513

84.5

Others

1,370

9,952,252

15.5

Single

1,882

16,846,557

26.2

Married

7,078

43,452,453

67.6

Marital status

Separate

67

218,162

0.3

Divorce

152

556,605

0.9

740

3,214,116

5.0

Widow

Logistic regression models were performed (presented as
odds ratio (OR) and corresponding 95% CI) to examine the
association between status of exposure to SHS among nonsmokers at home and selected socio-demographic factors.
Because education level was reported only among
respondents 25? years old, two models were constructed:
1 Model a: for all the study subjects (all aged 15 years
and over) education was excluded; and
2 Model b: for those aged 25 years and over and
education was included as an independent variable.

The models showed that the significant correlates of the
status of exposure to SHS at home were as listed in
Table 5.
•
•

Area
Urban

–
4,958

19,724,648

30.7

Rural

4,967

44,596,117

69.3

9,925

64,320,765

Total

occupation, Forestry/Fishing people (77.5%) and Farmers
(73.5%) had the highest exposure to SHS at home, whereas
Manager/Professional staff had the lowest (48.3%). There
was no specific pattern of exposure to SHS at home and at
work by economic status. However, the prevalence of
exposure to SHS at home among people in the higher
quintile was significantly higher than that among those in
the lower quintile (69.7% in quintile 1 and 55.6% in
quintile 5). By ethnicity, Kinh people had lower prevalence
of exposure to SHS at home compared with other ethnic
minority groups. There was no statistically significant
difference in the prevalence of exposure to SHS at work by
marital status. By residence, people living in rural areas
(72.0%) were more likely to be exposed than those living
in urban areas (57.7%).
Table 4 lists regulations on tobacco smoking at home in
Vietnam. Only 10.7% of the study respondents reported
that smoking is never allowed in their home. Most households had no indoor smoking rule (62.7%).

•

100

(65.2% vs. 68.8%, respectively). Exposure to SHS at home
decreased with increasing age. The highest exposure to
SHS at home was among those age 15–24 (74.2%) and the
lowest was among those 65 and above (57.2%). The
prevalence of exposure to SHS at home among nonsmoking women aged 15–44 was 72.4%. By education,
adults with primary education or less (71.5%) had the
highest prevalence of exposure to SHS at home and those

with college degrees or above (57.2%) had the lowest. By

•

•

•

Gender: Females were more likely than males to be
exposed to SHS at home.
Age: The prevalence of exposure to SHS at home
decreased with increasing age.
Occupation: People working as Service/Sales, Farmer,
and Production/Driving employees were more likely
than Manager/Professional staff to be exposed to SHS
at home.
Ethnicity: People belong to ethnic minority groups
were more likely than Kinh people to be exposed to
SHS at home.
Residence: People living in rural areas were more likely
than those living in urban areas to be exposed to SHS at
home.
Smoking restriction in the home: Exposure to SHS at
home was significantly prevalent in households where
smoking is allowed.

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Cancer Causes Control (2012) 23:99–107

Table 3 Pattern of SHS at home among non-smoking populations
by socio-demographic characteristics—GATS Vietnam, 2010 (n =
7563)
Characteristic

Prevalence of
SHS at home
(%)

Table 3 continued
Characteristic

95% CI of the prevalence
Lower bound
(%)

Upper bound
(%)

Male

65.2

62.7

67.1

Female

68.8

67.3

70.3

15–24

74.2

71.5

76.9

25–34

68.3

65.5

71.0

35–44

68.2

65.5

71.0

45–54

64.8

61.7

67.9

95% CI of the prevalence
Lower bound
(%)

Upper bound
(%)

66.2

68.9

Smoking is allowed at work
No

Gender

Prevalence of
SHS at home
(%)

67.6

Yes
67.0
58.2
75.7
Believed smoking causes stroke, heart attack, and lung cancer

Age

No

71.0

69.0

72.9

Yes

65.1

63.4

66.9

Believed SHS is dangerous
No

73.6

70.0

77.3

Yes

66.8

65.4

68.2

55–64

57.5

53.2

61.8

[64
Education

57.2

53.4

61.1

Primary

71.5

68.9

74.1

Secondary

66.8

64.7

68.8

High school

56.6

52.4

60.9

College, university

43.7

40.0

47.4

Indoor smoking is allowed

7.7

10.8

9.8

Indoor smoking is not allowed but
exceptions

19.9

15.1

16.5

Job

Table 4 Regulations on tobacco smoking at home in Vietnam,
GATS 2010 (n = 7,563)
Description

Urban
(%)

Rural
(%)

Overall
(%)

Manager/
Professional

48.3

42.9

53.7

Indoor smoking is never allowed

16.5

8.2

10.7

Office worker

58.3

48.7

67.2

No indoor smoking rule

55.7

65.9

62.7

Service/Sales

68.9

65.7

71.9

Do not know, no response

0.3

0.2

0.2

Farming

73.5

71.0

75.9

Forestry/Fishing
Construction/
Mining

77.5
66.2

62.7
55.4

87.5
75.5

Production/Driving

67.8

62.4

72.8

Others

63.0

53.5

71.6

Discussion

Quintile 1

69.7

66.9

72.5

Quintile 2

74.0

71.2

76.7

Quintile 3

73.8

70.7

76.8

Quintile 4

65.1

62.2

68.1

Quintile 5

55.6

52.8

58.5

70.9
68.0

68.2
66.5

73.6
69.5

The findings from this study showed that very many nonsmokers in Vietnam were exposed to SHS. Up to 67.6% of
non-smokers (equivalent to approximately 33 million
people) aged 15 and above were exposed to SHS at home.
The Vietnam National Health Survey 2001–2002 also
reported that 63% of households in Vietnam had at least
one smoker [14]. The prevalence of exposure to SHS at
home in Vietnam similar to that reported in the GATS
conducted in China (67.3%) [17], but was higher than the
corresponding figures found in the Philippines (44.8%) [18]

and in Thailand (39.1%) [19].
The high prevalence of exposure to SHS at home in
Vietnam can be explained by the fact that tobacco control
in the country has not yet prioritized a focus on smoke-free
homes. Furthermore, even though smoking is strictly prohibited in indoor workplaces and public places, for example schools, kindergartens, health facilities, libraries,
cinemas, theatres, and community cultural centers, and on

•

Education: People with lower educational level were
more likely to be exposed to SHS at home.

Asset quintile

Marital status
Single
Married
Separate

50.1

33.7

66.5

Divorce

48.2

36.6

59.8

Widow

51.5

46.8

56.3

Urban

57.7

55.9

59.5

Rural

72.0

70.3

73.7

Area

Smoking is allowed at home

No

65.3

63.9

67.0

Yes

88.5

85.6

91.4

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Cancer Causes Control (2012) 23:99–107

105

Table 5 Results from logistic regression analysis of the association
between exposure to SHS at home with selected socio-demographic
factors, among non-smokers—Vietnam GATS, 2010
Characteristic

Model 1a (Education
excluded, people aged

15?) OR (95% CI)

Model 1b (Education
included, people aged
25?) OR (95% CI)

Gender
Male

1.00

1.00

Female

1.2 [1.1–1.4]*

1.2 [1.1–1.4]*

Age group

Table 5 continued
Characteristic

Model 1a (Education
excluded, people aged
15?) OR (95% CI)

Model 1b (Education
included, people aged

25?) OR (95% CI)

Believed SHS is dangerous
No

1.00

1.00

Yes

0.8 [0.6–1.0]

0.9 [0.7–1.1]

Education
Primary

–

1.00

Secondary

–

0.7 [0.6–0.9]*

Aged 15–24

1.00

–

Aged 25–34

0.6 [0.5–0.8]

1.00

High school

–

0.6 [0.4–0.8]*

College, university

–

0.4 [0.3–0.6]*

Aged 35–44

0.6 [0.4–0.8]*

0.9 [0.7–1.0]

Aged 45–54

0.5 [0.4–0.7]*

0.7 [0.6–0.9]*

Aged 55–64

0.3 [0.2–0.5]*

0.5 [0.4–0.6]*

Aged [64

0.4 [0.3–0.5]*

0.4 [0.3–0.6]*

* p \ 0.05

Occupation
Manager/Professional

1.00

1.00

Office worker

1.4 (0.9–2.2)

1.3 (0.8–2.0)

Service/Sales

2.1 (1.6–2.7)*

1.7 (1.2–2.4)*

Farming

2.0 (1.5–2.6)*

1.6 (1.1–2.3)*

Forestry/Fishing

2.1 (1.0–4.4)

1.4 (0.6–3.1)

Construction/Mining

1.8 (1.0–3.1)

1.6 (0.9–2.9)

Production/Driving

1.8 (1.3–2.4)*

1.6 (1.1–2.4)*

Others

1.4 (0.9–2.1)

1.1 (0.7–1.8)

Asset quintile
Quintile 1

1.00

1.00

Quintile 2

1.4 [1.1–1.7]

1.2 [1–1.6]

Quintile 3

1.5 [1.2–1.8]

1.2 [1–1.6]

Quintile 4

1.3 [1.0–1.6]

1 [0.8–1.3]

Quintile 5

1.1 [0.9–1.4]

1 [0.8–1.3]

Ethnicity
Kinh (the majority)

1.00

1.00

Others

1.3 [1.1–1.7]*

1.4 [1.1–1.8]*

Single

0.9 [0.7–1.2]

0.8 [0.6–1.1]

Married

1.00

1.00

Separate

0.5 [0.3–0.9]

0.5 [0.2–0.9]

Divorce

0.5 [0.3–0.8]

0.5 [0.3–0.7]

Marital status

Widow
Area
Urban

1.00

1.00

Rural

1.4 [1.3–1.7]

1.2 [1–1.4]

Smoking is allowed at home
No

1.00

1.00

Yes

3.9 [2.9–5.4]*

3.9 [2.8–5.6]*

Smoking is allowed at work
No

1.00

1.00

Yes

0.7 [0.5–1.1]

0.7 [0.4–1.2]

Believed smoking causes stroke, heart attack, and lung cancer.
No

1.00

1.00

Yes

0.9 [0.8–1]

0.9 [0.8–1]

public transport (according to the government’s Decision
No. 1,315/QÐ-TTg), the prevalence of exposure to SHS at
work and in public places were still very high [20]. Violation of the smoke-free workplace and public places regulation has been shown to have negative effect on smoking
behaviour in private settings [21]. Legislation should
consider the issue of the smoke-free home in the near
future to protect children and vulnerable household members from SHS in the home. Community health education
programmes to raise public awareness and practice are also
needed to encourage families to make their homes smokefree, which would protect children and other family
members from the dangers of second-hand smoke. Scientific evidence has shown that voluntary smoke-free home
policies reduce exposure of children and adult non-smokers
to second-hand smoke, reduce smoking in adults, and seem
to reduce smoking in youths [22].
The GATS Vietnam 2010 revealed that females had
higher prevalence of exposure to SHS at home than males
and this finding implied that even though the prevalence of
smoking among Vietnamese women was low, they have
still been greatly exposed to the hazards of tobacco smoke.
This phenomenon could be explained by the fact that many
non-smoking women in Vietnam live with a male smoker
and they spend most of their time at home. This finding is

consistent with a study from China [23]. Our study
revealed that the prevalence of exposure to SHS at home
among non-smoking women of reproductive age was high
(72.4%). There is much published research, and studies are
now confirming that inhaling second hand cigarette smoke
also causes reproduction problems [1].
Our study also found that other disadvantaged people in
Vietnam, for example those belonging to ethnic minority
groups, rural dwellers, and people with lower education
were more likely to be exposed to SHS at home. This

123


106

indicates there is an inequity problem in exposure to SHS
at home in Vietnam. This finding is similar to those from
studies from China [23, 24], USA [25], and Spain [26], and
implies that tobacco control policies should pay special
consideration to these disadvantaged populations.
Our study demonstrated the effect of smoking restriction
in reducing the prevalence of exposure to SHS at home.
Similar findings were also obtained in studies in China [23,
24]. Because many households in Vietnam still have no
regulations restricting smoking at home, a smoke-free
household policy is necessary to reduce household SHS
exposure. In fact, the GATS Vietnam showed that most
adults supported smoke-free home regulations [27]. Promotion of smoke-free homes may be an important area to
emphasize in a tobacco control campaign.

Our study has several limitations. First, data from the
GATS on exposure to SHS are self-reported and no
objective measurement of levels of exposure to SHS was
conducted. Second, estimates of SHS exposure discussed
here did not consider duration of exposure. Third, the
cross-sectional design of the study does not enable us to
establish any causal connection.
In summary, the GATS Vietnam 2010 has shown that a
high percentage of people are exposed to second-hand
smoke at home. The significant correlates of the status of
exposure to SHS at home were female gender, ethnic
minority, low education, and lack of smoking restriction at
home. Because smoke-free homes have not been included
in tobacco-control policies, advocating of smoke-free
homes initiatives is urgently needed. Special considerations
should be given to disadvantaged people, because they are
more likely than the better-off to be exposed to SHS at
home, and to promoting community health-education programs to raise public awareness of the harm of tobacco use
and exposure to tobacco smoke. Further studies are also
needed to overcome the limitations of this study, for
example a study with objective measurement of level of
exposure to SHS (blood or urine cotinine) and study of
SHS exposure among children, women, the poor, etc.

Cancer Causes Control (2012) 23:99–107

2.

3.

4.
5.

6.

7.

8.
9.

10.

11.

12.

13.

14.
15.

16.

17.
Acknowledgments This study was funded by the Bloomberg Philanthropies. We highly appreciate the contributions to the success of
the survey made by the Centers for Disease Control and Prevention in
Atlanta, the CDC Foundation, the World Health Organization, the
General Statistics Office of Vietnam, and Hanoi Medical University.

18.

19.
20.

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