Abstract
Greater social capital has been shown to be associated with improved mental health, general wellbeing and reduced risk of premature mortality, cancer mortality and cardiovascular mortality. However, most of these studies found a positive relationship between social capital and health are limited to descriptive studies. This project is performing a theoretical approach to the role of social capital in producing health outcome based on Becker s household production function.
We are testing whether social capital has a positive impact on health both directly through a more effective production of health and indirectly through utilizing the health care system better, using several measurements of social capital from social support module in the National Health and Nutrition Examination Survey (NHANES) 2007-2008 for a sample of those 60 years old and above. NHANES is a unique data set in terms of collecting both subjective self-rated health status and several objective health outcome measurement through medical and laboratory examination.
Finding from 2SLS with instrumental variable was a bit surprising - various social capital measures do not show significant results in different experiments. The only exception is that more resources of emotional support can promote better overall health status.
Author Contributions
Copyright© 2018
Seo Bosu.
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Competing interests The authors have declared that no competing interests exist.
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Citation:
Introduction
“Why treat people’s illness without changing what makes them sick in the first place?” World Health Organization poses this question, suggesting that without modifying the social determinants of health, health care and medicine may be useless Social capital was explored as a social determinant of health in the public health domain and has become a popular topic in the past decade particularly with the publication of Putnam’s A growing body of literature has analyzed the concept of social capital and its impact on health outcomes and has attracted the attention of both the academic and the policy communities. For example, greater social capital has been shown to be associated with better levels of general health and (subjective) well-being, lower cardiovascular and cancer mortality, and lower suicide rates In this paper, we will explore social capital from the perspective of an individual resource and social connectedness, which refers to the relationships people have with others a. People enjoy constructive relationships with others in their families, communities, churches, and workplaces. Families support and nurture those in need of care. Social connectedness is integral to wellbeing. People are defined by their social roles, whether as partners, parents, children, friends, caregivers, teammates, staff or employers, or a pile of other roles. Relationships give people support, happiness, contentment and a sense they belong and have a role to play in society Most of the recent studies found a positive relationship between social capital and health in general, but they are limited to descriptive studies. The focus in this paper is on a theoretical approach to the role of social capital in producing health based on Becker’s household production function. This study is testing whether social capital has a positive impact on health status both directly through a more effective production of health and indirectly through utilizing the health care system better, using several measurements of social capital from the National Health and Nutrition Examination Survey (NHANES) 2007-2008 for a sample of those 60 years old and above b. A main reason to consider social capital in light of social networks/ connectedness of elderly people is that networks might enhance positive outcomes for seniors. Previous research reflects strong themes about the importance of family members and friends in the lives of older adults. Social ties have been linked to beneficial health and social outcomes, to the maintenance of independence in later life, and to responsive care for seniors with chronic long-term health problems In the literature, studies utilize subjective self-rated health status to explore the relationship between social capital and health. However, NHANES 2007-2008 allows us to use several objective measures, including medical and laboratory examination results as well as self-rated health status. These objective measures will allow us to conduct a more rigorous study about the impact of social capital on health outcomes.
Results
The descriptive statistics of all variables are presented in Source: NHANES 2007-2008 Sample: Adults who are 60 years old and above a) Codes are following: 1 - $0 to $4,999; 2 - $5,000 to $9,999 3 - $10,000 to $14,999; 4 - $15,000 to $19,999 5 - $20,000 to $24,999; 6 - $25,000 to $34,999 7 - $35,000 to $44,999; 8 - $45,000 to $54,999 9 - $55,000 to $54,999; 10 - $65,000 to $74,999 11 - $75,000 and over Self-rated health status shows similar patterns between males and females. About 70% of study participants evaluate themselves as either in excellent, very good, or good health (70.8% for males and 69.3 % for females). However, other health outcome measurements have a different distribution between males and females. Males usually show better health outcome than females. Males have 5.26 days of physical health that was not good during the past 30 days and 2.44 days of mental health that was not good during the past 30 days, while females have 6.61 days for poor physical health and 4.38 days for poor mental health. Males have less days of inactive days due to physical/mental health during the past 30 days (2.25 for males and 2.80 for females). Less than 5% of men had stomach or intestinal illness during the past 30 days, but almost twice as many women experienced it (7.6%). Regarding flu, pneumonia, or ear infection, in contrast to 4.1% of women, only 3.2% of males experienced these ailments during the past 30 days. Females are generally older than males by one year, have lower household annual income, and fewer females completed education surpassing high school (33.7% for females and 39.3% for males). One interesting finding from the socio-demographic variables is marital status. Only 37.2% of females are married while 72.4% of males are married and this is mainly due to the fact that the sample is adults 60 years old and above: women live longer than men and some females stay widowed once they lose their spouse. Also, a lower rate of second marriage for females may explain the gap. The race/ethnicity variable is derived by combining responses to questions on race and Hispanic origin. Sixty two percent of total group are Non-Hispanic White, 16.6% Non-Hispanic Black, 15.5% Mexican American, 3.3% Other Hispanic, and 2.5% of them are other race, including multi-race. This distribution still applies when the total sample is divided into males only and females only. Regarding social capital related factors, both males and females express similar responses. First, 91.5% of males and 93.5% of females have someone to help with emotional support in the last 12 months. Common resources of emotional support are spouse, children, and friends. More women needed more emotional support than males (16.0% for females and 10.7% of males) and around 60% of both males and females needed either a lot or some more emotional support (60.9% for males and 61.6% for females). Women also received more financial support in the past year than men (75.7% for males and 82.4% for females). Males have more close friends than females (8.32 for males and 7.64 for females). Social capital measurements should be treated as endogenous variables in the analysis, since a person’s health is likely to affect their social interaction. An estimation approach that does not explicitly address the simultaneous process will bias the estimated relationship between health outcome and the explanatory variables. The standard econometric procedure for handling endogeneity is some type of instrumental variables (IV) estimator, which is often employed in cross-sectional studies. Mostly two-stage least squares (TSLS) is employed, assuming an appropriate instrument is available. Instrumental variables should be theoretically correlated with the endogenous explanatory variables but not correlated with the error terms. One potential instrumental variable available in NHANES is the number of years the person has lived at their current address i. The longer the person has lived at their current address, the more likely they build social capital. However, this variable reflects past choices by the individual at certain point of time, so it is not correlated with the error term.
Total group
Males
Females
N
Mean or %
Stdev
N
Mean or %
Stdev
N
Mean or %
Stdev
Overall Health
1684
815
869
Excellent
9.5%
10.6%
8.5%
Very Good
24.3%
24.4%
24.2%
Good
36.2%
35.8%
36.6%
Fair
23.8%
22.9%
24.6%
Poor
6.1%
6.1%
6.0%
Don't know
0.1%
0.1%
0.1%
# of Days not good
Physical health
1683
5.95
12.25
815
5.26
11.79
868
6.61
12.63
Mental health
1682
3.44
10.10
815
2.44
7.49
867
4.38
11.98
# of Inactive Days
1681
2.53
9.04
815
2.25
8.04
866
2.80
9.89
Age
1872
71.06
1138.00
891
70.44
1033.99
981
71.52
1220.00
HH Annual Income (coded)a)
1643
6.63
804
7.13
839
6.24
Married
1868
54.0%
889
72.4%
979
37.2%
Race/Ethnicty
Non-Hispanic White
1164
62.2%
557
62.5%
607
61.9%
Non-Hispanic Black
310
16.6%
147
16.5%
163
16.6%
Mexican American
291
15.5%
137
15.4%
154
15.7%
Other Hispanic
61
3.3%
27
3.0%
34
3.5%
Other Race - Including Multirace
46
2.5%
23
2.6%
23
2.3%
Education
LT HS
738
39.5%
362
40.7%
376
38.4%
HS Grad (Including GED)
439
23.5%
175
19.7%
264
27.0%
MT HS
679
36.4%
349
39.3%
330
33.7%
Refused
4
0.2%
1
0.1%
3
0.3%
Don't know
8
0.4%
2
0.22
6
0.61
Emotional Support
Anyone helps
1727
92.5%
813
91.5%
914
93.5%
Spouse
817
43.6%
550
61.7%
267
27.2%
Daughter
801
42.8%
300
33.7%
501
51.1%
Son
620
33.1%
260
29.2%
360
36.7%
Sibling
286
15.3%
104
11.7%
182
18.6%
Parent
27
1.4%
14
1.6%
13
1.3%
Relatives
224
12.0%
78
8.8%
146
14.9%
Neighbor
74
4.0%
25
2.8%
49
5.0%
Co-worker
21
1.1%
10
1.1%
11
1.1%
Church
149
8.0%
62
7.0%
87
8.9%
Club member
9
0.5%
6
0.7%
3
0.3%
Professional
30
1.6%
9
1.0%
21
2.1%
Friends
454
24.3%
172
19.3%
282
28.7%
Others
56
3.0%
21
2.4%
35
3.6%
Needed more emotional support
233
13.5%
87
10.7%
146
16.0%
How much more
A lot
50
21.5%
19
21.8%
31
21.2%
Some
93
39.9%
34
39.1%
59
40.4%
A little
90
38.6%
34
39.1%
56
38.4%
Financial support
1872
79.2%
891
75.7%
981
82.4%
How many close friends
1840
7.94
1122.27
878
8.32
1214.42
962
7.64
1029.12
Conclusion
We have obtained MLE estimates of the coefficients for the probit regressions with instrumental variables predicting overall health status, physical health and mental health during the past 30 days separately j. The last two dependent variables can imply recent illness. 2SLS was utilized to obtain the estimate of the coefficients predicting index of biological risk factors. Regression results of the health demand equation are presented in Source: NHANES 2007-2008, age 60 and above Denotes significance at the 10% level Denotes significance at the 5% level *** Denotes significance at the 1% level 1. Dependent variable is overall health (=1 if oveall health status is excellent, very good, or good; = 0 if overall health status is fair or poor). Independent variables are age, gender, race (ref=non-hispanic white), country of born (ref= us born), education (ref=less than high school), marital status, household income, family disease history, and a social capital measure. Probit model with instrumental variable (years of residence at the current address) was utilized for an analysis. a. It was dropped due to collinearity in SAS. Source: NHANES 2007-2008, age 60 and above Denotes significance at the 10% level Denotes significance at the 5% level Denotes significance at the 1% level 1. Dependent variable is physical health (=0 if numbers of physical health was nood good during the past 30 days is zero; else = 1). Independent variables are age, gender, race (ref=non-hispanic white), country of born (ref= us born), education (ref=less than high school), marital status, household income, family disease history, and a social capital measure. Probit model with instrumental variable (years of residence at the current address) was utilized for an analysis. Source: NHANES 2007-2008, age 60 and above Denotes significance at the 10% level ** Denotes significance at the 5% level *** Denotes significance at the 1% level 1. Dependent variable is physical health (=0 if numbers of mental health was not good during the past 30 days is zero; else = 1). Independent variables are age, gender, race (ref=non-hispanic white), country of born (ref= us born), education (ref=less than high school), marital status, household income, family disease history, and a social capital measure. Probit model with instrumental variable (years of residence at the current address) was utilized for an analysis. Source: NHANES 2007-2008, age 60 and above Denotes significance at the 10% level Denotes significance at the 5% level Denotes significance at the 1% level 1. Dependent variable is biological risks (=summation of inflammation, metabolic, and cardiovascular risk factors). Independent variables are age, gender, race (ref= non-hispanic white), country of born (ref= us born), education (ref=less than high school), marital status, household income, family disease history, and a social capital measure. 2SLS model (; instrumental variable=years of residence at the current address) was utilized for an analysis. In general, blacks and Mexican Americans are in poorer health than whites. A similar pattern holds for people who were born in Mexico compared with U.S. born. Each table includes 5 separate regressions with one of five social capital measures: numbers of emotional support sources, emotional support from any source, financial support from any source, either emotional or financial support from any source, and number of close friends. Surprisingly, the social capital measures do not show significant results except in one case. The only exception is that more resources of emotional support can promote better overall health status, as shown in equation 1 in Social capital, at least in terms of the variables that are available to measure in the NHANES 2007-2008, do not affect health outcomes of elderly people, at least the ones analyzed in this study. This unexpected finding does not necessarily imply social capital has little impact on health of elderly people. Rather, it opens further questions of refining the models and statistical analysis, including exploring other omitted variables. Maybe our instrumental variable was not suitable for the analyses. Or we may have to accept that the basic hypothesis regarding the effect of social capital on health may simply be rejected in this particular case. In terms of future research on this topic, we plan to use factor analysis to extract common factors in defining social capital. Factor analysis is a method of data reduction. It does this by seeking underlying unobservable (latent) variables that are reflected in the observed variables (manifest variables). In this study, we used a summary index of biological risk factor using nine indicators. We will utilize other indexing methods and define separate inflammation risk, metabolic risk, and cardiovascular risk with other measures k.
Estimate
Pr > |Z|
Estimate
Pr > |Z|
Estimate
Pr > |Z|
Estimate
Pr > |Z|
Estimate
Pr > |Z|
age
-0.011
0.097
-0.006
0.857
-0.027
0.207
-0.027
0.858
-0.023
0.929
male
0.221
0.215
-1.023
0.721
0.359
0.459
2.235
0.885
-1.051
0.939
black
-0.417
0.003
-0.474
0.547
-0.619
0.058
-0.223
0.897
-16.247
0.941
mexican
-0.495
0.004
-1.128
0.616
-0.381
0.076
1.841
0.904
-9.539
0.939
otherrace
-0.545
0.033
0.825
0.824
-0.418
0.196
-2.722
0.865
-7.905
0.938
mexicoborn
-0.759
0.001
-4.194
0.679
-0.558
0.070
5.513
0.895
-6.256
0.934
otherborn
0.036
0.873
0.005
0.996
0.116
0.669
0.102
0.965
-7.461
0.943
hs
(dropped)a)
(dropped)
(dropped)
(dropped)
(dropped)
mths
(dropped)
(dropped)
(dropped)
(dropped)
(dropped)
married
-0.439
0.038
1.157
0.751
-0.145
0.322
-2.363
0.877
8.970
0.942
hhinc
0.114
0.001
0.347
0.528
0.049
0.586
-0.372
0.913
0.967
0.932
famhis
-0.009
0.927
-0.218
0.728
-0.069
0.563
0.107
0.946
0.245
0.959
ssnum
0.851
0.080
emoss
-39.213
0.725
finss
4.843
0.354
anyss
107.935
0.883
numfriends
-5.824
0.941
Estimate
Pr > |Z|
Estimate
Pr > |Z|
Estimate
Pr > |Z|
Estimate
Pr > |Z|
Estimate
Pr > |Z|
age
0.005
0.374
0.001
0.992
0.020
0.360
0.013
0.825
0.004
0.937
male
-0.357
0.023
0.438
0.841
-0.558
0.256
-1.139
0.802
0.069
0.971
black
0.006
0.963
0.082
0.883
0.189
0.544
-0.124
0.867
4.875
0.884
mexican
0.345
0.021
0.739
0.655
0.291
0.128
-0.647
0.884
2.796
0.872
otherrace
0.169
0.435
-0.657
0.801
0.074
0.800
0.96
0.825
2.381
0.88
mexicoborn
0.037
0.85
2.181
0.767
-0.147
0.623
-2.448
0.833
1.95
0.886
otherborn
0.124
0.507
0.149
0.846
0.091
0.706
0.045
0.961
2.371
0.882
hs
(dropped)
(dropped)
(dropped)
(dropped)
(dropped)
mths
(dropped)
(dropped)
(dropped)
(dropped)
(dropped)
married
0.205
0.273
-0.766
0.771
-0.145
0.322
0.879
0.834
-2.761
0.884
hhinc
-0.018
0.271
-0.156
0.723
0.049
0.586
0.164
0.858
-0.283
0.872
famhis
-0.034
0.669
0.109
0.817
-0.069
0.563
-0.117
0.862
-0.107
0.913
ssnum
-0.514
0.222
emoss
24.323
0.764
finss
-4.173
0.427
anyss
-42.537
0.834
numfriends
1.783
0.884
Estimate
Pr > |Z|
Estimate
Pr > |Z|
Estimate
Pr > |Z|
Estimate
Pr > |Z|
Estimate
Pr > |Z|
age
-0.009
0.149
-0.005
0.848
-0.024
0.284
-0.02
0.841
-0.01
0.906
male
-0.117
0.471
-1.097
0.640
0.095
0.850
1.319
0.899
-0.824
0.882
black
-0.129
0.309
-0.201
0.762
-0.335
0.318
0.038
0.978
-9.271
0.923
mexican
-0.140
0.381
-0.627
0.727
-0.082
0.715
1.527
0.880
-5.004
0.922
otherrace
-0.165
0.476
0.917
0.765
-0.169
0.618
-1.755
0.872
-4.348
0.923
mexicoborn
0.048
0.824
-2.704
0.748
0.271
0.406
4.616
0.871
-3.379
0.927
otherborn
0.022
0.913
-0.002
0.999
0.104
0.708
0.069
0.968
-4.263
0.926
hs
(dropped)
(dropped)
(dropped)
(dropped)
(dropped)
mths
(dropped)
(dropped)
(dropped)
(dropped)
(dropped)
married
-0.325
0.096
-0.766
0.771
-0.112
0.463
-1.738
0.868
5.121
0.925
hhinc
-0.031
0.088
-0.156
0.723
-0.099
0.296
-0.386
0.868
0.487
0.927
famhis
0.142
0.103
0.109
0.817
0.130
0.299
0.242
0.830
0.348
0.897
ssnum
0.634
0.159
emoss
-31.171
0.735
finss
4.786
0.379
anyss
-42.537
0.834
numfriends
-3.379
0.923
Estimate
Pr > |Z|
Estimate
Pr > |Z|
Estimate
Pr > |Z|
Estimate
Pr > |Z|
Estimate
Pr > |Z|
age
-0.013
0.009
-0.002
0.985
-0.021
0.258
-0.011
0.046
-0.015
0.316
male
-0.054
0.679
0.497
0.925
0.069
0.877
-0.041
0.844
-0.124
0.509
black
0.309
0.003
0.511
0.775
0.212
0.489
0.349
0.011
-0.702
0.879
mexican
-0.122
0.129
0.374
0.928
-0.145
0.314
-0.016
0.948
-0.704
0.796
otherrace
-0.268
0.113
-0.719
0.865
-0.227
0.322
-0.271
0.237
-0.832
0.755
mexicoborn
0.206
0.558
3.533
0.902
0.324
0.240
0.564
0.526
-0.192
0.920
otherborn
-0.070
0.247
0.154
0.936
-0.035
0.854
-0.031
0.866
-0.642
0.812
hs
(dropped)
(dropped)
(dropped)
(dropped)
(dropped)
mths
(dropped)
(dropped)
(dropped)
(dropped)
(dropped)
married
-0.023
0.865
-0.572
0.918
0.049
0.611
-0.001
0.999
0.663
0.818
hhinc
-0.065
0.001
-0.232
0.874
-0.099
0.224
-0.081
0.145
-0.003
0.991
famhis
0.254
0.001
0.003
0.999
0.228
0.008
0.211
0.127
0.297
0.302
ssnum
0.173
0.614
emoss
28.386
0.908
finss
2.025
0.673
anyss
4.100
0.698
numfriends
-0.397
0.825